DE102007004961A1 - Preparing a catalyst molded body, useful e.g. to prepare catalyst for gas phase partial oxidation of an organic compound, comprises molding a precursor mixture to a desired geometry, using graphite, and thermally treating the molded body - Google Patents

Abstract

Preparation of a catalyst molded body whose active mass is a multi-element oxide, comprises molding a finely-divided precursor mixture to a desired geometry by adding a graphite having a specific surface of 0.5-5 m 2>/g and an average particle diameter (d 5 0) of 40-200 mu m; and thermally treating the obtained catalyst precursor molded body at increased temperature. An independent claim is included for the catalyst molded body, obtained from the above process.

Description

This Invention relates to a process for the preparation of shaped catalyst bodies, whose active material is a Mulitelementoxid, in which one finely divided Precursor mixture, which acts as a finely divided molding aid (or forming aid) contains added graphite, to the desired geometry forms (compacted) and the case resulting catalyst precursor moldings at elevated temperature to obtain the shaped catalyst bodies, whose active material is a Mulitelementoxid, thermally treated.

Furthermore, the present invention relates to methods of heterogeneously catalyzed gas phase reactions, for. B. gas phase partial oxidation of organic compounds in which the aforementioned shaped catalyst bodies are used as catalysts. Examples of such heterogeneously catalyzed partial oxidation processes are the preparation of acrolein from propylene ( WO 2005/030393 ), the production of methacrylic acid from methacrolein ( EP-A 467 144 ) and the production of maleic anhydride from n-butane ( WO 01/68245 ).

acrolein forms, for example, an important intermediate in the production of acrylic acid produced by heterogeneously catalyzed partial Oxidation of acrolein is available. acrylic acid forms a significant monomer, as such or in the form of its Alkyl ester can be polymerized radically. The resulting Polymers are u. a. as superabsorbent materials or as adhesives. Similarly, methacrylic acid is also suitable as such or in the form of their alkyl esters for the preparation of free-radical Polymers. An outstanding position takes z. B. the Methyl esters of methacrylic acid, in particular to Production of polymethyl methacrylate finds use as Plastic glass is used. Maleic anhydride an important intermediate in the synthesis of γ-butyrolactone, tetrahydrofuran and 1,4-butanediol, which in turn act as a solvent used or for example to polymers such as polytetrahydrofuran or polyvinylpyrrolidone be further processed.

Under a complete oxidation of an organic compound With molecular oxygen is understood in this document that the organic compound under the reactive action of molecular Oxygen is converted to that in the organic compound total contained carbon in oxides of carbon and the total hydrogen contained in the organic compound Oxides of hydrogen is converted. All of them different Reactions of an organic compound under reactive action of molecular oxygen are referred to here as partial oxidations of a combined organic compound.

in the special in this document under partial oxidation such Reactions of organic compounds under reactive action be understood by molecular oxygen, in which the partially too oxidizing organic compound after completion of the reaction at least contains an oxygen atom more chemically bound than before Carrying out the partial oxidation. The concept of partial Oxidation is in this document but also the oxidative dehydrogenation and partial ammoxidation, d. h., a partial oxidation in the presence of ammonia.

It is generally known that multielement oxides (in particular multimetal oxides) are in particular suitable active materials for catalysts for carrying out heterogeneously catalyzed partial oxidation of organic compounds in the gas phase (cf., for example, all in US Pat DE-A 103 53 014 as well as in the DE-A 103 60 396 listed heterogeneously catalyzed partial oxidation).

Initially described method for the preparation of shaped catalyst bodies are z. B. from the scriptures WO 01/68245 . WO 2005/030393 . DE-A 10 2005 035 978 . EP-A 1 060 792 . WO 03/078310 . WO 03/78059 . DE-A 10 2005 037 678 . EP-A 467 144 and previously known from Research Disclosure RD 2005-497012. The majority of the abovementioned publications in this case measures the nature of the graphite used as shaping assistant with regard to the performance of the resulting shaped catalyst body (in particular as a catalyst for heterogeneously catalyzed partial oxidation of organic compounds in the gas phase) of no importance at all.

Only in embodiments of the WO 2005/030393 and in Comparative Examples of Research Disclosure RE 2005-497012, it is noted without value that the specific surface area of the graphite used was 6 to 13 m ² / g and its particle diameter d _{50 had} a value of 19.3 μm.

D. h., The addition of the molding aid graphite takes place in the Catalyst shaped article production in the abovementioned publications essentially exclusively as a lubricant, d. H., to reduce the mechanical wear of the forming tools.

The US-A 2005/0131253 relates to a process for the preparation of shaped catalyst bodies based on multielement oxides with the concomitant use of finely divided graphite as molding aid with a particle diameter d ₅₀ of 10 to 50 microns. In the exemplary embodiments, d _{50 is} 31 and 29 μm. As an essential property of the finely divided graphite but not its particle size, but its "combustion initiating temperature" is considered, which should be at least 50 ° C above the applied calcination temperature.

adversely however, in the described prior art methods, that they influence the texture of the grain used as shaping aid finely divided graphite on the catalytic appearance (especially used finely divided Graphite on the catalytic appearance (in particular on the selectivity of target product formation when heterogeneous with them catalyzed partial gas phase oxidations of organic starting compounds) did not recognize the resulting shaped catalyst body. Against this background, the object of the present invention therein, an improved process for the preparation of shaped catalyst bodies to provide, in particular the catalyst molding resulting in particular improved target product selectivities when used as catalysts for heterogeneously catalyzed partial gas-phase oxidations of organic starting compounds enable.

• a) für die spezifische Oberfläche O_G des feinteiligen Graphit gilt: 0,5 m²/g ≤ O_G ≤ 5 m²/g, und
• b) für den Partikeldurchmesser d₅₀ des feinteiligen Graphit zutrifft: 40 μm ≤ d₅₀ ≤ 200 μm.

Accordingly, a process for producing shaped catalyst bodies whose active composition is a multielement oxide, and in which a finely divided precursor mixture containing added as a finely divided molding aid graphite, molded to the desired geometry (compacted) and the resulting Katalysatorforläuferformkörper at elevated temperature to give the Catalyst shaped body whose active composition is a multi-element oxide, thermally treated, found, which is characterized in that

• a) for the specific surface O _{G of} the finely divided graphite: 0.5 m ² / g ≤ O _G ≤ 5 m ² / g, and
• b) for the particle diameter d _{50 of} the finely divided graphite: 40 μm ≤ d ₅₀ ≤ 200 μm.

D. h., the use of limited compared to the prior art coarse-grained graphite, the inventive Task to solve.

Of the Catalyst molding can, for. B. a ball with a diameter from 2 to 10 mm, or a solid cylinder with an outside diameter and a height of 2 to 10 mm, or a ring whose outside diameter and height 2 to 10 mm and its wall thickness 1 to 3 mm, be.

Particularly advantageous according to the invention are those processes for producing shaped catalyst bodies which use finely divided graphite as shaping aids, for which it is true that on the one hand 40 μm ≦ d ₅₀ ≦ 200 μm, and on the other hand 0.5 m ² / g ≦ O _G ≦ 4 m ² / g, preferably 0.75 m ² / g ≦ O _G ≦ 3 m ² / g, particularly preferably 1 m ² / g ≦ O _G ≦ 2.5 m ² / g and very particularly preferably 1.25 m ² / g ≦ O _G ≤ 2.5 m ² / g or 1.5 m ² / g ≤ O _G ≤ 2 m ² / g.

The use of finely divided graphites of this kind as shaping aids is particularly advantageous, for which it is true that, on the one hand, 50 μm ≦ d ₅₀ ≦ 200 μm and, on the other hand, 0.5 m ² / g ≦ O _G ≦ 5 m ² / g, preferably 0, 5 m ² / g ≦ O _G ≦ 4 m ² / g, more preferably 0.75 m ² / g ≦ O _G ≦ 3 m ² / g, particularly preferably 1 m ² / g ≦ O _G ≦ 2.5 m ² / g and most preferably 1.25 m ² / g ≦ O _G ≦ 2.5 m ² / g or 1.5 m ² / g ≦ O _G ≦ 2 m ² / g.

Even more advantageous according to the invention is the use of such finely divided graphites as shaping aids, for which it is true that on the one hand 60 μm (or 70 μm) ≦ d ₅₀ ≦ 200 μm, and on the other hand 0.5 m ² / g ≦ O _G ≦ 5 m ² / g , preferably 0.5 m ² / g ≦ O _G ≦ 4 m ² / g, more preferably 0.75 m ² / g ≦ O _G ≦ 3 m ² / g, particularly preferably 1 m ² / g ≦ O _G ≦ 2, 5 m ² / g and most preferably 1.25 m ² / g ≦ O _G ≦ 2.5 m ² / g or 1.5 m ² / g ≦ O _G ≦ 2 m ² / g.

The most advantageous, however, according to the invention is the use of such finely divided graphites as shaping aids, for which it is true that, on the one hand, 90 μm (or 100 μm) ≦ d ₅₀ ≦ 170 μm, and, on the other hand, 0.5 m ² / g ≦ O _G ≦ 5 m ² / g, preferably 0.5 m ² / g ≦ O _G ≦ 4 m ² / g, more preferably 0.75 m ² / g ≦ O _G ≦ 3 m ² / g, particularly preferably 1 m ² / g ≦ O _G ≦ 2 , 5 m ² / g and most preferably 1.25 m ² / g ≦ O _G ≦ 2.5 m ² / g or 1.5 m ² / g ≦ O _G ≦ 2 m ² / g.

It is also advantageous according to the invention if, in the abovementioned pattern, the particle diameters d ₁₀ and d _{90 of} the finely divided graphite at a d ₅₀ of ≥ 90 μm and ≦ 200 μm simultaneously fulfill the following conditions:
20 μm ≤ d ₁₀ ≤ 90 μm, and
150 μm ≤ d ₉₀ ≤ 300 μm.

As a rule, d ₁₀ <d ₅₀ <d ₉₀ .

in principle can for the inventive method both synthetic (synthetically produced) and natural (naturally occurring) graphite are used. According to the invention preferred is the use of natural graphite because of this Its pronounced layer structure particularly favorable lubricant properties (Lubricant properties). Completely according to the invention particularly advantageous natural graphites are those which are substantially free of mineral contaminants.

Furthermore, it is advantageous for the preparation process according to the invention if, during the thermal treatment, the catalyst precursor molded body until the catalyst molding is obtained (the catalytically active multielement oxide composition forms from the precursor composition) at least 1% by weight, preferably at least 2% by weight, more preferably at least 3% by weight, and most preferably at least 5% by weight, of the amount by weight of graphite (calculated as pure amount of carbon) contained in the catalyst precursor moldings is converted into gaseous escaping compounds (for example to CO and / or CO ₂ burned) is. According to the invention, the abovementioned proportion by weight of the amount by weight of graphite (calculated as the pure amount of carbon) contained in the catalyst precursor moldings during the thermal treatment of the catalyst precursor moldings until the catalyst moldings are obtained is advantageously not more than 70% by weight, preferably not more than 60 Wt .-%, more preferably not more than 50 wt .-% and most preferably not more than 40 wt .-% or not more than 30 wt .-%. From an application point of view, the aforementioned weight proportion is 5 to 15% by weight.

typical Graphite use amounts to the inventive Method to 0.1 to 20, or 0.5 to 10, or 1 to 5 wt .-% (calculated as pure carbon and based on the mass of the catalyst precursor body).

Usually is the finely divided precursor mixture, which acts as a finely divided Forming aids (compaction aids) finely divided according to the invention Graphite added, during molding dry (touch-dry).

In The rule contains the finely divided precursor mixture the graphite to be added according to the invention as the only one Forming aids added. In principle, the inventive Addition of graphite but also together with other shaping aids such as B. boron nitride, carbon black, polyethylene glycol, stearic acid, starch, Polyacrylic acid, mineral or vegetable oil, water, finely divided Teflon powder (eg powder from Aldrich 43093-5) and / or boron trifluoride to the finely divided precursor mixture respectively.

The thermal treatment of the catalyst precursor moldings can advantageously be carried out according to the invention and adapted to the individual type of the desired multielement oxide (active) composition at temperatures (which act from the outside on the catalyst moldings) of from 150 to 650 ° C. Frequently, the thermal treatment of the catalyst precursor moldings at temperatures in the range of 200 ° C to 600 ° C, or 250 ° C to 550 ° C, or 300 ° C to 500 ° C take place. The duration of the thermal treatment may extend over a period of a few hours to several days. The thermal treatment can be carried out under vacuum, under an inert atmosphere (eg N ₂ , noble gases, water vapor, CO _2, etc.), under a reducing atmosphere (eg H ₂ or NH ₃ ) or under an oxidizing atmosphere. In general, oxidizing atmospheres will contain molecular oxygen. Typical oxidizing atmospheres are mixtures of inert gas (N ₂ , noble gases, water vapor, CO ₂ etc.) and molecular oxygen. The content of molecular oxygen is usually at least 0.1% by volume, frequently at least 0.2% by volume, often at least 0.5% by volume, often at least 1% by volume, or at least 10% by volume. , or at least 20 vol .-% amount. Of course, the content of molecular oxygen in such mixtures may also be 30 vol.%, Or 40 vol.%, Or 50 vol.%, Or 70 vol.%, Or more.

Of course comes as an atmosphere for the thermal treatment but also pure molecular oxygen into consideration. Often the thermal treatment will take place under air. Generally speaking the thermal treatment of the catalyst precursor moldings under standing or under flowing gas atmosphere (z. B. in the air stream).

The term of the atmosphere (or the gas atmosphere) in which the thermal treatment takes place is to be understood in this document as meaning that it does not comprise developing catalyst gases from the catalyst precursor moldings during the thermal treatment due to decomposition processes. Of course, the gas atmosphere in which the thermal treatment takes place, but also exclusively or partially composed of these gases. Within the scope of the thermal treatment taking place in the method according to the invention, both the treatment temperature and the treatment atmosphere can be designed to be constant over time or else variable in time over the duration of the treatment.

There Graphite as a carbon-containing substance is combustible takes place the thermal treatment of the finely divided graphite added according to the invention containing catalyst precursor moldings in known in terms of application technology appropriate usually such that this is in the catalyst precursor moldings do not contain graphite during the thermal treatment ignited, so on the outside the thermal treatment on the catalyst precursor moldings optionally acting temperature in the molding interior far-reaching temperatures (so-called hot spot temperatures in Calcinationsgut) as far as possible, since such temperature peaks the catalytic quality of the resulting shaped catalyst bodies can reduce. This objective requires in particular then a certain care, if the atmosphere in which the thermal treatment takes place, molecular oxygen as such and / or molecular oxygen supplying components and / or from the composition of the precursor composition itself resulting in a graphite oxidizing effect. It is too take into account that naturally occurring graphite usually a mixture of graphite and mineral constituents is that can catalyze an inflammation of the graphite. Also affect the grain and the surface texture of the graphite used according to the invention Inflammatory behavior.

In this connection, it is of general advantage for the method according to the invention if the temperature T _i (the sample temperature or, more precisely, the oven temperature) at which a weight loss is observed for the first time in a simultaneous differential scanning calorimetry thermogravimetry of the graphite to be used according to the invention (T _i should be referred to in this document as the "temperature of the beginning of incineration") is at least 50 ° C, preferably at least 75 ° C, more preferably at least 100 ° C, preferably at least 125 ° C and more preferably at least 150 ° C greater than those in As part of the inventive thermal treatment of the catalyst precursor moldings to this acting for a period of at least 30 minutes highest temperature.

Since the result of a determination of T _i by means of a simultaneous differential scanning calorimetry thermal gravimetry is not only a function of the graphite to be checked with this method, but also a pronounced function of the selected verification frame (eg also of the examined sample quantity), FIG Temperature T _i used in this specification is based on the verification principle described below, including the specified verification framework:
The graphite sample to be tested (sample amount = 10 mg) is placed in an open sample crucible (Al ₂ O ₃ ) in a vertical tube furnace tester (Netzsch STA 449 C Jupiter ^® , instrument type: simultaneous thermal analysis, coupling of dynamic heat flow difference calorimeter and compensating thermal balance with vertical tube furnace) of NETZSCH-Gerätebau GmbH, Wittelsbacherstrasse 42, D-95100 Selb / Bavaria subjected to a predetermined temperature program (heating rate = 0.3 K / min, temperature range = 30 ° C (start temperature) to 1000 ° C (final temperature )). The furnace atmosphere used is air at a flow rate of 20.0 cm ³ / min.

Depending on the furnace temperature, the heat flow from and to the sample is determined from the temperature difference between the graphite sample to be tested and an empty inert reference sample crucible (Al ₂ O ₃ ) in a defined thermal contact with the sample. Sample crucible with sample, reference sample crucible without sample and the temperature sensors are located on a scale. As a result, thermogravimetry (TG) is possible simultaneously with dynamic differential calorimetry (DSC = Dynamic Scanning Calorimetry) (= method for measuring the mass change (or weight change) of a sample in the course of the temperature program; from the oven temperature).

The TG resolution is 0.1 μg and the DSC resolution is <1 μW. Moreover, the test is carried out in accordance with DIN 51006 and DIN 51007. T _i values of graphites to be used according to the invention 500 ° C., preferably ≥ 550 ° C., prove to be advantageous in the case of many preparation processes according to the invention. In general, however, T _i is at values ≦ 700 ° C., usually ≦ 650 ° C.

For the method according to the invention, it is furthermore advantageous if, in the above-described thermogravimetry of the graphite to be used according to the invention, the temperature T _m (sample temperature or better oven temperature) at which the decrease in the mass of the graphite sample reaches its maximum value with the increase in temperature ( In this document, T _m is advantageously ≥ 680 ° C. for graphites to be used according to the invention. preferably ≥ 700 ° C, and more preferably ≥ 750 ° C. As a rule, T _m is ≤ 900 ° C, many times ≤ 850 ° C.

In addition, it is favorable for the method according to the invention if, in the above-described thermogravimetry of the graphite according to the invention, the temperature T _f (sample temperature or better oven temperature) from which no further weight loss is observed (at which the weight loss is completed) is 150 to 350 ° C (suitably 250 ° C) above T _i .

It should be noted at this point that all information in this document relating to specific surfaces of graphite refers to determinations according to DIN 66131 (determination of the specific surface area of solids by gas adsorption (N ₂ ) according to Brunauer-Emmet-Teller (BET)).

All Information in this document on total pore volumes and pore diameter distributions on these total pore volumes as well as on specific surfaces (in each case of the catalyst moldings) relate on determinations by the method of mercury porosimetry in Application of the device Auto Pore 9220 from Micromeritics GmbH, 4040 Neuss, DE (bandwidth 30 Å to 0.3 mm). Furthermore the method of determination is given.

For the determination of particle diameter distributions and the particle diameters d ₁₀ , d ₅₀ and d ₉₀ taken from these, the respective finely divided powder was introduced via a dispersing trough into the dry disperser Sympatec RODOS (Sympatec GmbH, System-Particle Technology, Am Pulverhaus 1, D-38678 Clausthal, Germany). Zellerfeld) and where it is dispersed dry with compressed air and blown into the measuring cell in the free jet. In this case, the volume-related particle diameter distribution is then determined according to ISO 13320 with the laser diffraction spectrometer Malvern Mastersizer S (Malvern Instruments, Worcestshire WR14 1AT, United Kingdom). The particle diameter d _x indicated as the measurement result is defined such that X% of the total particle volume consists of particles with this or a smaller diameter.

to Determination of graphite content (calculated as pure carbon quantity) in the catalyst precursor moldings and finished Catalyst molding can be z. B. a representative Grind the number of the respective shaped bodies to a powder.

The determination is then carried out on a respectively identical amount of fraction which has absolutely suitably a mass of 50 to 20 mg. This powdery sample is then placed in the presence of an oxygen stream in a heated to about 1000 ° C horizontal quartz tube and annealed. The combustion gas thus obtained is passed through an IR cell and quantitatively determined by the amount of carbon dioxide contained in this by infrared absorption. From the amount of detected carbon dioxide, the respective graphite content (calculated as pure carbon amount) can be back-calculated (cf. "Quantitative Organic Elemental Analysis", VON Verlagsgesellschaft mbH, Weinheim, Issue 1991; ISBN: 3-527-28056-1, page 225 et seq ).

The Particle diameter of the finely divided precursor mixture (excluding the added forming aid) (for at least 90% of the weight of the precursor mixture) its shaping to the desired geometry of the Katalysatorvorläuferformkörpers usually in the range of 10 to 2000 microns. frequently the aforementioned particle diameters are in the range from 20 to 1800 μm, or 30 to 1700 μm, or 40 to 1600 μm, or 50 to 1500 microns lie. Becoming very common this particle diameter 100 to 1500 microns, or 150 to 1500 microns.

in the As a rule, the shaping (compaction) of the finely divided precursor mixture takes place to the geometry of the Katalysatorvorläuferformkörpers by external forces (pressure) on the finely divided precursor mixture. The applicable Shaping apparatus or the forming method to be used is subject to no restriction. Likewise subject the desired geometry of the Katalysatorvorläuferformkörpers no restriction. That is, the catalyst precursor moldings can be regular or irregular be shaped, with regularly shaped moldings are usually preferred.

Of the Catalyst precursor shaped body can be spherical geometry exhibit. In this case, the ball diameter z. B. 2 to 10 mm, or 4 to 8 mm. The geometry of the catalyst precursor body but can also be fully cylindrical or hollow cylindrical.

In both cases, outside diameter and height z. B. 2 to 10 mm or 2 or 4 to 8 mm. In the case of hollow cylinders is usually a wall thickness of 1 to 3 mm appropriate. Selbstver Of course, as catalyst precursor geometry, however, all those geometries are also considered which are described in US Pat WO 02/062737 disclosed and recommended. As a rule, in the method according to the invention, the geometry of the resulting shaped catalyst body deviates only insignificantly from the geometry of the shaped catalyst precursor body.

It should be noted at this point that according to the invention particularly advantageous processes for the preparation of shaped catalyst bodies and thus particularly favorable shaped catalyst bodies result if, in the research disclosure Disclosure RE 2005-497012, EP-A 1 060 792 . DE-A 10 2005 035 978 . DE-A 10 2005 037 678 . WO 03/78059 . WO 03/78310 . DE-A 198 55 913 . WO 02/24620 . DE-A 199 22 113 . WO 01/68245 . EP-A 467 114 . US-A 2005/0131253 . WO 02/062737 and WO 05/030393 disclosed manufacturing process at the points where finely divided graphite is co-used, according to the invention uses graphite to be used and retains all other manufacturing measures unchanged. The resulting shaped catalyst bodies are then in a completely corresponding manner as in the publications DE-A 199 22 113 . WO 01/68245 . EP-A 467 114 . DE-A 198 55 913 . US-A 2005/0131253 . WO 02/24620 . WO 03/78059 . WO 03/078310 . WO 02/062737 , Research Disclosure RD 2005-4979012, EP-A 1 060 792 . DE-A 10 2005 035 978 . DE-A 10 2005 037 678 , and WO 05/030393 used for the corresponding heterogeneously catalyzed gas phase reactions. They are particularly advantageous if the graphite used is the natural graphite Asbury 3160 and / or the synthetic graphite Asbury 4012 from Asbury Graphite Mills, Inc. New Jersey 08802, USA. In particular, when using synthetic graphite, it is usually beneficial for the lubricating properties to apply increased amounts of the graphite to be used.

The Shaping can in the method according to the invention z. B. by extrusion, tabletting or extrusion. This is the finely divided precursor mixture, as already mentioned, usually used dry touched. However, it can be added up to 10% of its total weight substances which are liquid under normal conditions (25 ° C, 1 atm) are. The inventive method is but applicable even if the finely divided precursor mixture at all contains no such liquid substances more. Of course, the finely divided precursor mixture but also consist of solid solvates (such as hydrates), such liquid substances in chemical and / or physical have bound form.

The molding pressures used in the process according to the invention will generally be 50 kg / cm ² to 5000 kg / cm ² . Preferably, the forming pressures are from 200 to 3500 kg / cm ² , more preferably from 600 to 2500 kg / cm ² . The above is particularly true when tableting is used as the molding process. The basic features of tabletting are z. B. in "The Tablet", Handbook of Development, Production and Quality Assurance, WA Ritschel and A. Bauer-Brandl, 2nd edition, Editio Cantor Verlag Aulendorf, described in 2002 and in a completely corresponding manner transferable to a tabletting method according to the invention.

When Multielementoxidmassen come within the scope of the invention Process considered both active compounds, in addition to oxygen contain both metals and non-metals as elemental constituents. Often these are the multielement oxide (active) compounds but to mass pure multimetal oxide (active).

For an application of the method according to the invention particularly favorable Multielementoxid (active) masses including associated precursor compositions are, for. For example, those in the scriptures WO 2005/030393 . EP-A 467 144 . EP-A 1 060 792 . DE-A 198 55 913 . WO 01/68245 . EP-A 1060792 , Research Disclosure RD 2005-497012, WO 03/078310 . DE-A 102005035978 . DE-A 102005037678 . WO 03/78059 . WO 03/078310 . DE-A 199 22 113 . WO 02/24620 . WO 02/062737 and US-A 2005/0131253 are disclosed.

Usable according to the invention finely divided precursor mixtures are in the simplest way z. B. obtainable from sources of elementary Constituents of the desired active mass (multielement oxide mass) a finely divided, intimate as possible, the stoichiometry the desired active mass accordingly assembled, formed moldable mixture, the still shaping and optionally Reinforcing aids can be added (and / or can be incorporated from the beginning).

Suitable sources of the elemental constituents of the desired active composition are, in principle, those compounds which are already oxides and / or those compounds which undergo heating, at least in the presence of gaseous molecular oxygen and / or gaseous oxygen-releasing components , into oxides are convertible. In principle, the oxygen source but also z. B. be in the form of a peroxide component of the precursor mixture itself. Also, that can Precursor mixture compounds such as NH ₄ OH, (NH ₄ ) ₂ CO ₃ , NH ₄ NO ₃ , NH ₄ CHO ₂ , CH ₃ COOH, NH ₄ CH ₃ CO ₂ , ammonium oxalate and / or organic components such. B. stearic acid added, which decompose in the thermal treatment as a pore former to completely gaseous escaping compounds and / or can be decomposed.

The, preferably intimate, mixing of the starting compounds (sources) for the preparation of the finely divided, formable precursor mixture can be carried out in the process according to the invention in dry or in wet form. If it takes place in dry form, the starting compounds are expediently used as finely divided powders (with a particle diameter d ₅₀ in the range 1 to 200 .mu.m, preferably 2 to 180 .mu.m, more preferably 3 to 170 .mu.m and most preferably 4 to 160 .mu.m, or 5 to 150 μm or 10 to 150 μm, or 15 to 150 μm). After addition of the shaping aids according to the invention and, if appropriate, additional addition of further shaping and / or amplifier aids, the shaping can subsequently take place. Such reinforcing aids may be, for example, microfibers made of glass, asbestos, silicon carbide and / or potassium titanate. Quite generally, in the process according to the invention, a starting compound can be a source of more than one elemental constituent.

Instead of forming the finely divided precursor mixture as such directly to the desired geometry, it is often useful to first intermediate compact it as a first shaping step to coarsen the powder (typically particle diameter d ₅₀ from 100 to 2000 microns, preferably 150 to 1500 μm, more preferably 400 to 1000 μm).

there can according to the invention before the intermediate compaction graphite used as Kompaktierhilfsmittel be added. Subsequently, based on the coarsened Powder the final (actual) shaping, where If necessary, before again finely divided according to the invention Graphite (and optionally further shaping and / or reinforcing agents) can be added.

According to the invention, however, the intimate mixing is carried out in wet form. Usually, the starting compounds z. B. in the form of an aqueous (but also liquids such as iso-butanol come as a solution and / or dispersing medium into consideration) solution and / or suspension mixed together. Particularly intimately formable mixtures are obtained when it is assumed that only the sources of elementary constituents present in dissolved form. Water is preferably used as the solvent (but liquids such as isobutanol are also suitable as solvents). Subsequently, the resulting solution or suspension is dried, wherein the drying process is preferably carried out by spray drying with outlet temperatures of 100 to 150 ° C (in some cases, the drying can also be done by filtration and subsequent drying of the filter cake). The particle diameter d _{50 of} the resulting spray powder is typically 10 to 50 μm. If water is the base of the liquid medium, the resulting spray powder will normally contain no more than 20% of its weight, preferably not more than 15% of its weight, and more preferably not more than 10% by weight of its weight of water. These percentages usually apply even when using other liquid solvents or suspending aids. After addition of the molding aids according to the invention to the particular powdered dry mass and optionally further shaping and / or reinforcing agents, the powdery mixture can be compacted (shaped) according to the invention as a finely divided precursor mixture to give the desired catalyst precursor shaped body. However, the finely divided shaping and / or reinforcing aids can also be added in advance (partially or completely) to the spray mixture.

A only partial removal of the solvent or suspending agent may also be appropriate if its co-use is intended as a molding aid.

advance the inventive addition of the finely divided Graphits can already be a first thermal treatment of the Dry powder done. After addition of the graphite is then the Shaping and the inventive thermal Further treatment.

Instead of the finely divided precursor mixture based on the spray powder as such, to form immediately the desired geometry, It is often convenient, as a first Forming step, first an intermediate compaction to coarsen the powder (in usually on particle diameter of 100 to 2000 microns, preferably 150 to 1500 .mu.m, more preferably 400 to 1000 μm).

In this case, according to the invention, graphite to be used according to the invention may be added as compacting assistant before the intermediate compaction. Subsequently, on the basis of the coarsened powder, the final (actual) shaping, wherein, if necessary, once again finely divided graphite according to the invention (and optionally further shaping and / or reinforcing aids) can be added.

Of course can be used as sources of elemental constituents and starting compounds in turn, by thermal treatment of precursor moldings produced and are multielementoxidischer nature. Especially can be the starting compounds of elemental constituents be multimetallic nature.

The inventive method is particularly suitable for the preparation of shaped catalyst bodies whose active composition is a multi-element oxide within which the element Mo (or the elements V and P) are the most frequently numerically (molar) occurring element is. In particular, it is suitable for the production of shaped catalyst bodies whose active composition is a multielement oxide is that the elements Mo, Fe and Bi, or the elements Mo and V, or the elements Mo, V and P or the elements V and P comprises. The former catalyst bodies in the aforementioned Series are particularly suitable for heterogeneously catalyzed partial Gas phase oxidations of propylene to acrolein. The second mentioned Catalyst moldings are especially suitable for heterogeneously catalyzed partial gas phase oxidations of acrolein to acrylic acid, the penultimate catalyst shaped body in the aforementioned series are especially suitable for heterogeneous catalyzed partial gas phase oxidations of methacrolein Methacrylic acid and the latter catalyst bodies are especially suitable for heterogeneously catalyzed partial Gas phase oxidations of n-butane to maleic anhydride.

In particular, the present invention comprises a process for the preparation of annular shaped catalyst bodies (also called full catalysts, since they have no inert support body, on which the active composition is applied) with curved ter and / or non-curved end face of the rings whose active material (in the active composition remaining graphite is as always disregarded in this document, since it normally behaves chemically inert and is not catalytically active) a stoichiometry of the general formula I, Mo ₁₂ Bi _a Fe _b X ¹ _c X ² _d X ³ _e X ⁴ _f O _n (I) With
X ¹ = nickel and / or cobalt,
X ² = thallium, an alkali metal and / or an alkaline earth metal,
X ³ = zinc, phosphorus, arsenic, boron, antimony, tin, cerium, lead, vanadium, chromium and / or tungsten,
X ⁴ = silicon, aluminum, titanium and / or zirconium,
a = 0.2 to 5,
b = 0.01 to 5,
c = 0 to 10,
d = 0 to 2,
e = 0 to 8,
f = 0 to 10 and
n = a number which is determined by the valence and frequency of the elements other than oxygen in I,
or a stoichiometry of the general formula II, [Y ¹ _{a '} Y ² _b' O _{x '} ] _p [Y ³ _c' Y ⁴ _{d '} Y ⁵ _e' Y ⁶ _{f '} Y ⁷ _g' Y ⁸ _{h '} O _y' ] _q (II) With
Y ¹ = only bismuth or bismuth and at least one of tellurium, antimony, tin and copper,
Y ² = molybdenum or tungsten, or molybdenum and tungsten,
Y ³ = an alkali metal, thallium and / or samarium,
Y ⁴ = an alkaline earth metal, nickel, cobalt, copper, manganese, zinc, tin, cadmium and / or mercury,
Y ⁵ = iron or iron and at least one of the elements vanadium, chromium and cerium,
Y ⁶ = phosphorus, arsenic, boron and / or antimony,
Y ⁷ = a rare earth metal, titanium, zirconium, niobium, tantalum, rhenium, ruthenium, rhodium, silver, gold, aluminum, gallium, indium, silicon, germanium, lead, thorium and / or uranium,
Y ⁶ = molybdenum or tungsten, or molybdenum and tungsten,
a '= 0.01 to 8,
b '= 0.1 to 30,
c '= 0 to 4,
d '= 0 to 20,
e '= 0 to 20,
f '= 0 to 6,
g '= 0 to 15,
h '= 8 to 16,
x ', y' = numbers which are determined by the valence and frequency of the elements other than oxygen in II and
p, q = numbers whose ratio p / q is 0.1 to 10,
and whose annular geometry, without taking into account any existing curvature of the end face, a height H of 1.5 to 8 mm, an outer diameter A of 2 to 11 mm and a wall thickness W of 0.75 mm to 2.0 mm.

at This method is derived from sources of elementary constituents the active composition is a finely divided formable precursor mixture produce and from this mixture, after adding inventive Forming aids and optionally further shaping and / or Reinforcing aids, annular unsupported catalyst precursor bodies shapes whose faces are curved and / or not are curved, and these by thermal treatment at Transfer elevated temperature in the annular unsupported catalysts.

Furthermore The present invention relates to the use of the above According to the invention available annular Full catalysts as catalysts with increased selectivity (at comparable activity) for the gas-phase catalytic Partial oxidation of propene to acrolein and of isobutene or tert-butanol or its methyl ether to methacrolein.

The The aforesaid process for the production of the annular Catalyst molding is particularly advantageous when the shaping (compaction) of the finely divided precursor mixture so that the lateral compressive strength of the resulting annular Full catalyst precursor moldings ≥ 10 and ≤ 40 N, better ≥ 10 and ≤ 35 N, still better ≥ 12 N and ≤ 23 N. Preferably is the lateral compressive strength of the resulting annular Full catalyst precursor shaped body ≥ 13 N and ≤ 22 N, or ≥ 14 N and ≤ 21 N. Ganz the lateral compressive strength is particularly preferably resulting annular unsupported catalyst precursor moldings ≥ 16 N and ≤21 N.

Further is the grain size for these types of catalysts (the particle diameter) of the finely divided precursor mixture (except the adjuvant aids) advantageously 200 microns up to 1500 .mu.m, particularly advantageously 400 .mu.m to 1000 μm (eg adjusted by intermediate compaction). Conveniently, at least 80 wt .-%, better at least 90% by weight and more preferably at least 95 or 98 or more wt .-% of the finely divided precursor mixture in this grit area. As side pressure resistance is doing in this document, the compressive strength at compression of the annular Unsupported catalyst precursor body vertical to the cylindrical envelope (i.e., parallel to the surface the ring opening) understood. All lateral compressive strengths are related this document to a determination by means of a material testing machine of Company Zwick GmbH & Co (D-89079 Ulm) of the type Z 2.5 / TS15. This material testing machine is for quasistatic stress with brisk, designed to rest, swell or alternate course. she is suitable for tensile, compression and bending tests. The installed Force transducer of the type KAF-TC of the company A. S. T. (D-01307 Dresden) with the serial number 03-2038 was in accordance with the DIN EN ISO 7500-1 calibrated and was for the measuring range 1-500 N can be used (relative measurement uncertainty: + 0.2%).

The measurements were carried out with the following parameters:
Pre-load: 0.5 N.
Pre-load speed: 10 mm / min.
Test speed: 1.6 mm / min.

there The upper punch was initially slow until just before the Surface of the cylindrical envelope of the annular Fully catalyst precursor molded body lowered. Then the upper punch was stopped to subsequently with the significantly slower test speed with minimal, to further lowering necessary to be reduced Vorkkraft.

The Vorkraft, wherein the Vollkatalysatorvorläuferformkörper Cracking is the side crushing strength (SDF).

According to particularly advantageous Vollkatalysatorringgeometrien additionally meet the Bedin H / A = 0.3 to 0.7. Particularly preferred is H / A = 0.4 to 0.6.

Farther is it advantageous for the relevant unsupported catalyst rings when the ratio I / A (where I is the inner diameter of the Full catalyst ring geometry is) 0.3 to 0.8, preferably 0.4 to 0.7.

Especially advantageous are Vollkatalysatorringgeometrien simultaneously one of the advantageous H / A ratios and one of have advantageous I / A ratios.

Such possible combinations are z. B. H / A = 0.3 to 0.7 and I / A = 0.3 to 0.8 or 0.4 to 0.7. Alternatively, H / A can be 0.4 to 0.6 and I / A at the same time be 0.3 to 0.8 or 0.4 to 0.7.

Further is it preferable for the relevant unsupported catalyst rings, when H is 2 to 6 mm, and particularly preferred when H is 2 to 4 mm.

Farther It is advantageous if A is 4 to 8 mm, preferably 5 to 7 mm.

The Wall thickness of the invention available relevant Vollkatalysatorringgeometrien is advantageous 1 to 1.5 mm.

D. h., Cheap said Vollkatalysatorringgeometrien are z. For example, those with H = 2 to 6 mm and A = 4 to 8 mm or 5 to 7 mm. Alternatively, H can be 2 to 4 mm and A can be 4 to 8 mm at the same time 5 to 7 mm. In all the above cases can the wall thickness W 0.75 to 2.0 mm or 1 to 1.5 mm.

Especially preferred are among the aforementioned favorable Vollkatalysatorgeometrien those in which at the same time the aforementioned H / A and I / A combinations are met.

Possible relevant full catalyst ring geometries are thus (A × H × I) 5 mm × 2 mm × 2 mm, or 5 mm × 3 mm × 2 mm, or 5 mm × 3 mm × 3 mm, or 5.5 mm × 3 mm × 3.5 mm, or 6 mm × 3 mm × 4 mm, or 6.5 mm × 3 mm × 4.5 mm, or 7 mm × 3 mm × 5 mm, or 7 mm × 7 mm × 3 mm, or 7 mm × 7 mm × 4 mm.

The faces of the rings as described can also either either or only one as in the EP-A 184 790 be described curved and although z. B. such that the radius of curvature is preferably 0.4 to 5 times the outer diameter A. According to the invention, both end faces are unconstrained.

All These Vollkatalysatorringgeometrien are suitable for. For both the gas-phase catalytic partial oxidation of propene to acrolein as well as for the gas-phase catalytic partial oxidation of isobutene or tert-butanol or the methyl ether of tert-butanol to methacrolein.

Concerning the active materials of the stoichiometry of the general formula I, the stoichiometric coefficient b is preferably 2 to 4, the stoichiometric coefficient c preferably 3 to 10, the stoichiometric coefficient d is preferable 0.02 to 2, the stoichiometric coefficient e is preferable 0 to 5 and the stoichiometric coefficient is a preferably 0.4 to 2. The stoichiometric coefficient f is before geous 0.5 or 1 to 10. Particularly preferred the aforementioned stoichiometric coefficients are simultaneous in the said preferred areas.

Further, X ^{1 is} preferably cobalt, X ² is preferably K, Cs and / or Sr, particularly preferably K, X ³ is preferably tungsten, zinc and / or phosphorus and X ⁴ is preferably Si. Particularly preferred are the variables X ¹ to X ⁴ simultaneously have the meanings given above.

Particularly preferably, all the stoichiometric coefficients a to f and all variables X ¹ to X ⁴ simultaneously have their aforementioned advantageous meanings.

Within the stoichiometries of the general formula II are those which are of the general formula III [Bi _{a ''} Z ² _{b ''} O _{x ''} ] _{p ''} [Z ⁸ ₁₂ Z ³ _{c ''} Z ⁴ _{d ''} Fe _{e ''} Z ⁵ _{f ''} Z ⁶ _{g ''} Z ⁷ _{h ''} O _y'' ] _q'' (III), With
Z ² = molybdenum or tungsten, or molybdenum and tungsten,
Z ³ = nickel and / or cobalt,
Z ⁴ = thallium, an alkali metal and / or an alkaline earth metal, preferably K, Cs and / or Sr,
Z ⁵ = phosphorus, arsenic, boron, antimony, tin, cerium, vanadium, chromium and / or Bi,
Z ⁵ = silicon, aluminum, titanium and / or zirconium, preferably Si,
Z ⁷ = copper, silver and / or gold,
Z ⁸ = molybdenum or tungsten, or tungsten and molybdenum
a '' = 0.1 to 1,
b '' = 0.2 to 2,
c '' = 3 to 10,
d "= 0.02 to 2,
e "= 0.01 to 5, preferably 0.1 to 3,
f '' = 0 to 5,
g '' = 0 to 10, preferably> 0 to 10, particularly preferably 0.2 to 10 and very particularly preferably 0.4 to 3,
h '' = 0 to 1,
x '', y '' = numbers which are determined by the valence and frequency of the elements other than oxygen in III and
p ", q" = numbers whose ratio p "/ q" is 0.1 to 5, preferably 0.5 to 2.

Furthermore, active materials of stoichiometry II are preferred, which contain three-dimensionally expanded regions of the chemical composition Y ¹ _{a '} Y ² _b' O _{x '} , which are delimited from their local environment due to their different composition from their local environment, whose largest diameter (longest through the center of gravity the area of the connecting distance of two points located on the surface (interface) of the area) is 1 nm to 100 μm, often 10 nm to 500 nm or 1 μm to 50 or 25 μm.

Particularly advantageous active materials of stoichiometry II are those in which Y ^{1 is} only bismuth.

Within the active materials of stoichiometry III those are preferred according to the invention in which Z ² _{b ''} = (tungsten) _{b ''} and Z ⁸ ₁₂ = (molybdenum) ₁₂ .

Furthermore, for the discussed annular unsupported catalysts, active materials of stoichiometry III are preferred, which contain regions of the chemical composition Bi _{a "} Z ² _b" O _{x "} , which are three-dimensionally expanded and demarcated from their local environment due to their different composition from their local environment. whose largest diameter (longest through the center of gravity of the range going distance of two located on the surface (interface) of the area points) 1 nm to 100 .mu.m, often 10 nm to 500 nm or 1 micron to 50 or 25 microns, is.

Furthermore, it is advantageous if at least 25 mol% (preferably at least 50 mol% and particularly preferably at least 100 mol%) of the total fraction [Y ¹ _{a '} Y ² _b' O _{x '} ] _p ([Bi _a'' Z ² _b'' O _x'' ] p) of the active materials of stoichiometry II (active materials of stoichiometry III) obtainable as described in the active materials of stoichiometry II (active materials of stoichiometry III) in the form of three-dimensionally extended, from their local environment due to their Regions of chemical composition Y ¹ _{a '} Y ² _b' O _{x '} ([Bi _{a "} Z ² _b" O _{x "} ]) present in their local environment of different chemical composition, whose largest diameters range from 1 nm to 100 microns is.

When Forming aids (lubricants) come for the inventive Process for the preparation of the relevant annular shaped catalyst bodies in addition to graphite according to the invention, Polyethylene glycol, stearic acid, starch, polyacrylic acid, Mineral or vegetable oil, water, boron trifluoride and / or Boron nitride into consideration. Also, glycerol and cellulose ethers can be used as another lubricant. According to the invention preferred is exclusively according to the invention using graphite added as a shaping aid. Based on the to Vollkatalysatorvorläuferformkörper total mass to be formed is generally ≦ 15% by weight, usually ≦ 9% by weight, often ≦ 5% by weight, often ≦ 4 % By weight of graphite to be used according to the invention added. Usually, the aforementioned Additional amount ≥ 0.5 wt .-%, usually ≥ 2.5 wt .-%. Prefers added graphites according to the invention are Asbury 3160 and Asbury 4012.

Further can be finely divided reinforcing agents such as microfibers glass, asbestos, silicon carbide or potassium titanate. The molding to the annular unsupported catalyst precursor body can z. B. by means of a tabletting machine, an extrusion molding machine or the like.

The thermal treatment of the relevant annular unsupported catalyst precursor body usually occurs at temperatures exceeding 350 ° C. Normally, as part of the thermal treatment, the temperature of 650 ° C, however, not exceeded. According to the invention advantageous is within the scope of the thermal treatment, the temperature of 600 ° C, preferably the temperature of 550 ° C and more preferably the temperature of 500 ° C was not exceeded. Further, in the context of thermal treatment of the annular Full catalyst precursor molding preferably the temperature of 380 ° C, with advantage the temperature of 400 ° C, with particular advantage the temperature of 420 ° C. and most preferably the temperature of 440 ° C exceeded. In this case, the thermal treatment in its timing also be divided into several sections. For example, can first a thermal treatment at a temperature from 150 to 350 ° C, preferably 220 to 290 ° C, followed by a thermal treatment at a Temperature of 400 to 600 ° C, preferably 430 to 550 ° C. be performed.

Usually takes the thermal treatment of the annular unsupported catalyst precursor body several hours (usually more than 5 h) to complete. Often the total duration of the thermal treatment extends to more than 10 h. Most are used in the context of thermal treatment of annular unsupported catalyst precursor body Treatment periods of 45 h or 25 h not exceeded. Often the total treatment time is less than 20 hours. According to the invention advantageous be in the context of thermal treatment of the relevant annular Full catalyst precursor tablet 500 ° C (460 ° C) and the duration of treatment in the temperature window of ≥ 400 ° C (≥ 440 ° C) extends to 5 to 20 h.

The thermal treatment (also referred to below as the decomposition phase) of the annular unsupported catalyst precursor moldings can be carried out both under inert gas and under an oxidative atmosphere such as. As air (mixture of inert gas and oxygen) and also under reducing atmosphere (eg., Mixture of inert gas, NH ₃ , CO and / or H ₂ or methane, acrolein, methacrolein) take place. Of course, the thermal treatment can also be carried out under vacuum.

In principle, the thermal treatment of the relevant annular unsupported catalyst precursor moldings in a variety of furnace types such. B. heated circulating air chambers, Hordenöfen, rotary kilns, Bandcalzinierern or shaft furnaces are performed. The thermal treatment of the annular unsupported catalyst precursor moldings preferably takes place in a belt calcining apparatus such as the one described in US Pat DE-A 100 46 957 and the WO 02/24620 recommend.

The thermal treatment of the relevant annular unsupported catalyst precursor moldings below 350 ° C usually pursues the goal of thermal decomposition of in the unsupported catalyst precursor bodies contained sources of elementary constituents of the aspired annular unsupported catalyst. Often done This decomposition phase during heating to temperatures ≥ 350 ° C.

The annular unsupported catalyst precursor body of targeted annular unsupported catalysts whose Active composition has a stoichiometry of the general formula I, or the general formula II, or the general formula III can be made by one of Sources of elemental constituents of the active mass of the desired annular unsupported catalyst (as intimate as possible) finely divided, the stoichiometry of the desired Active mass produced correspondingly composed, moldable mixture and from this, after addition of (inter alia, according to the invention) Shaping and optionally reinforcing aids, an annular unsupported catalyst precursor body (with curved and / or non-curved face) whose lateral compressive strength is ≥ 12 N and ≤ 23 N is. The geometry of the annular unsupported catalyst precursor body is substantially that of the desired annular Full catalyst correspond.

When Sources for the elemental constituents of the desired Active compounds are those compounds in which it are already oxides and / or such compounds, the by heating, at least in the presence of molecular oxygen, are convertible into oxides.

In addition to the oxides, suitable starting compounds in particular are halides, nitrates, formates, oxalates, citrates, acetates, carbonates, amine complexes, ammonium salts and / or hydroxides (compounds such as NH ₄ OH, (NH ₄ ) ₂ CO ₃ , NH ₄ NO ₃ , NH ₄ CHO ₂ , CH ₃ COOH, NH ₄ CH ₃ CO ₂ , ammonium oxalate and / or organic components such as stearic acid, which decompose and / or decompose to completely gaseous compounds during thermal treatment may additionally be incorporated into the finely particulate mouldable mixture (preferably a dry blend)).

The, preferably intimate, mixing of the starting compounds (sources) to produce the fine The moldable mixture can be carried out in the process according to the invention in dry or wet form. If it is carried out in dry form, the starting compounds are expediently used as finely divided powders (the particle diameter d ₅₀ should advantageously be ≦ 100 μm, preferably ≦ 50 μm, as a rule the particle diameter d _{50 will be} ≥ 1 μm). After addition of (inter alia inventive) shaping and optionally reinforcing aids, shaping can then be carried out to form the annular unsupported catalyst precursor molding.

Preferably, however, the intimate mixing takes place in wet form. Usually, the starting compounds are mixed together in the form of an aqueous solution and / or suspension. Particularly intimately formable mixtures are obtained when it is assumed that only the sources of elementary constituents present in dissolved form. The solvent used is preferably water. Subsequently, the resulting solution or suspension is dried, wherein the drying process is preferably carried out by spray drying with outlet temperatures of 100 to 150 ° C. The particle diameter d _{50 of} the resulting spray powder is typically 10 to 50 μm, preferably 15 to 40 μm.

The Spray powder can now be added after addition of (i.a. Forming and optionally reinforcing aids the annular unsupported catalyst precursor moldings compacted (molded). The finely divided molding and optionally Reinforcement aids can also already Advance spray drying (partial or complete) be added. Also during drying, the solution or suspending agents are only partially removed, if its Co-use is intended as a molding aid.

Instead of the spray powder after addition of (inter alia) according to the invention Shaping and optionally reinforcing aids, directly to the annular unsupported catalyst precursor moldings (with curved and / or non-curved end face of the rings), it is often convenient first carry out an intermediate compaction, to coarsen the powder (usually on a grit from 400 μm to 1 mm). Followed by the coarsened powder the actual ring forming, wherein If necessary, once again finely divided according to the invention Lubricant can be added.

A such intermediate compaction for the purpose of grain coarsening For example, by means of a compactor from. Hosokawa Bepex GmbH (D-74211 Leingarten), type Kompaktor K 200/100. The hardness of Zwischenkompaktats is often already in the range of 10 N. For the ring shaping to the unsupported catalyst precursor body comes z. B. a Kilian rotary (the Fa. Kilian in D-50735 Cologne) of the type RX 73 or S 100 into consideration. alternative can a tablet press Fa. Korsch (D-13509 Berlin) of the type PH 800-65 are used.

In particular for the preparation of active materials of the stoichiometry of the general formula II or III, it is advantageous to use a mixed oxide Y ¹ _{a '} Y ² _b' O _{x '} or Bi _{a "} Z ² _b" O _{x "} as the source of the elements Y ¹ , Y ² or Bi, Z ² in the absence of the remaining constituents of the active materials of the stoichiometry of the general formula II or III and thus according to its pre-formation, as already described, with sources of the remaining constituents of the active materials of the stoichiometry of the general formula II or III to produce a finely divided moldable mixture in order to form therefrom, after addition of (inter alia) inventive molding and optionally reinforcing aids the annular Vollkatalysatorvorläuferformkörper.

In such an approach, it is merely necessary to ensure that, in the event that the preparation of the fine-particle-formable mixture takes place wet (in suspension), the preformed mixed oxides Y ¹ _{a '} Y ² _b' O _{x '} or Bi _{a "} Z ² _{b ''} O _{x ''} do not go to any appreciable extent in solution.

In detail, a manufacturing method as described above in the writings DE-A 44 07 020 . EP-A 835 . EP-A 575 897 and DE-C 33 38 380 described.

For example, one may mix water-soluble salts of Y ¹ such as nitrates, carbonates, hydroxides or acetates with Y ² acids or their ammonium salts in water, dry the mixture (preferably spray-drying) and then thermally treat the dried mass. The thermally treated composition is subsequently suitably comminuted (for example in a ball mill or by jet milling) and from the powders which are available, generally consisting essentially of essentially spherical particles, the particle size with an im of the general formula for the active composition of the stoichiometry II or III desired largest diameter range lying grain size diameter separated by in a known manner to be performed classification (eg wet or dry screening) and preferably with, based on the mass of this separated grain class, 0.1 to 3 wt .-%, finely divided SiO ₂ (the particle diameter d _{50 of} the usual Example, substantially spherical SiO ₂ particles is suitably 100 nm to 15 microns) mixed and prepared as a starting material 1. The thermal treatment is advantageously carried out at temperatures of 400 to 900 ° C, preferably at 600 to 900 ° C. The latter applies in particular when the preformed mixed oxide is one of the stoichiometry BiZ ² O ₆ , Bi ₂ Z ² ₂ O ₉ and / or Bi ₂ Z ² ₃ O ₁₂ , among which the Bi ₂ Z ² ₂ O _{9 is} preferred, especially when Z ² = tungsten.

Usually, the thermal treatment takes place in the air stream (eg in a rotary kiln, as used in the DE-A 103 25 487 is described). The duration of the thermal treatment usually extends to a few hours.

Of the other constituents of the desired active composition of the general formula II or III is normally starting from in a conventional manner suitable sources (see. EP-A 835 and DE-C 33 38 380 such as DE-A 44 07 020 ) in accordance with the invention suitably z. B. a very intimate, preferably finely divided dry mixture prepared (eg, water-soluble salts such as halides, nitrates, acetates, carbonates or hydroxides in an aqueous solution and then the aqueous solution, for example, spray-dry or non-water-soluble salts, eg Oxides, suspended in an aqueous medium and then, for example, the suspension is spray-dried), which is referred to herein as the starting material 2. It is only important that the constituents of the starting material 2 are either already oxides, or such compounds which can be converted into oxides by heating, if appropriate in the presence of oxygen. Subsequently, the starting material 1 and the starting material 2 in the desired ratio in accordance with the invention, ie after addition of (inter alia) molding and optionally reinforcing agents, the formable for the annular Vollkatalysatorvorläuferformkörper mixture mixed. The shaping can, as already described, be carried out appropriately in terms of application technology via the stage of intermediate compaction.

In a less preferred embodiment, the preformed mixed oxide Y ¹ _{a '} Y ² _b' O _{x '} or Bi _a'' Z ² _b'' O _x'' with sources of the remaining constituents of the desired active composition in liquid, preferably aqueous, Medium intimately mixed. This mixture is then z. B. dried to an intimate dry mix and then, as already described, molded and thermally treated. In this case, the sources of the remaining constituents may be dissolved and / or suspended in this liquid medium, whereas the preformed mixed oxide should be substantially insoluble in this liquid medium, ie it must be suspended.

The Preformed mixed oxide particles are in the finished annular Full catalyst in the longest extent set by the classification essentially unchanged.

Preferably, the specific surface area of such preformed mixed oxides Y ¹ _{a '} Y ² _b' O _{x '} or Bi _{a "} Z ² _b" O _{x "is} 0.2 to 2, particularly preferably 0.5 to 1.2 m ² / g. Furthermore, the total pore volume of such preformed mixed oxides advantageously results predominantly in micropores.

Advantageous relevant annular unsupported catalysts are those whose specific surface area is 0 5 to 20 or 15 m ² / g, frequently 5 to 10 m ² / g. The total pore volume V of such annular unsupported catalysts is advantageously in the range of 0.1 to 1 or 0.8 cm ³ / g, often in the range 0.2 to 0.4 cm ³ / g.

As a rule, shaped catalyst bodies produced according to the invention have a limited increase in that pore diameter d ^max whose pores having their diameter make the largest percentage contribution in their total number to the total pore volume of the shaped catalyst body produced according to the invention. This could be the cause of the inventively observed increase in the target product selectivity achieved with catalyst moldings produced according to the invention.

In typically, the side compressive strengths are as described Available annular catalysts 5 up to 13 N, often 8 to 11 N. These lateral compressive strengths from annular as available Full catalysts are usually present even if the rest advantageous physical properties described (eg. O, V and pore diameter distribution) of available as described annular unsupported catalysts are present.

As already mentioned, the annular unsupported catalysts obtainable as described are particularly suitable as catalysts for the partial oxidation of propene to acrolein or of isobutene and / or tert. Butanol to methacrolein. The partial oxidation can be z. B. as in the scriptures WO 00/53557 . WO 00/53558 . DE-A 199 10 506 . EP-A 1,106,598 . WO 01/36364 . DE-A 199 27 624 . DE-A 199 48 248 . DE-A 199 48 523 . DE-A 199 48 241 . EP-A 700 714 . DE-A 10313213 . DE-A 103 13 209 . DE-A 102 32 748 . DE-A 103 13 208 . WO 03/039744 , EP-A 279 374 . DE-A 33 38 380 . DE-A 33 00 044 . EP-A 575 897 . DE-A 10 2004 003 212 . DE-A 10 2005 013 039 . DE-A 10 2005 009 891 . DE-A 10 2005 010 111 . DE-A 10 2005 009 885 such as DE-A 44 07 020 described, wherein the catalyst charge z. B. only as described available annular unsupported catalysts or z. B. may comprise diluted inert catalysts with inert shaped bodies. In the latter case, the catalyst charge is advantageously designed so that its volume-specific activity in the flow direction of the reaction gas mixture increases continuously, abruptly and / or stepwise.

there In particular, those in this document are individualized highlighted ring geometries of the available as described Full catalysts are then considered advantageous when the load on the catalyst feed with propene contained in the starting reaction gas mixture, isobutene and / or tert. Butanol (or its methyl ether) ≥ 130 Nl / l catalyst charge · h is (pre- and / or Residues of pure inert material are under load considerations not considered as belonging to the catalyst feed). This especially if the others in this document described as advantageous physical properties of how described available annular catalysts given are.

This advantageous behavior of as available available annular unsupported catalysts, in particular the abovementioned is also present if the aforementioned load of the catalyst feed ≥ 140 Nl / lh, or ≥ 150 Nl / lh, or ≥ 160 Nl / lh. Normally, the aforementioned Loading of the catalyst charge ≤ 600 Nl / l · h, frequently ≦ 500 Nl / l · h, often ≦ 400 Nl / l · h or ≤ 350 Nl / l · h. charges in the range of 160 Nl / l · h to 300 or 250 or 200 Nl / l · h are very typical.

Of course can the available as described annular Unsupported catalysts as catalysts for the partial oxidation of propene to acrolein or of isobutene and / or tert. butanol (or its methyl ether) to Methacrolein even at loads of Catalyst charge with the partially oxidized starting compound of <130 Nl / l · h, or ≦ 120 Nl / l · h, or ≦ 110 Nl / l · h, operate. In general, however, this load is at values ≥ 60 Nl / lh, or ≥70 Nl / lh, or ≥80 Nl / lh.

• a) die Belastung der Katalysatorbeschickung mit Reaktionsgasausgangsgemisch; und/oder
• b) den Gehalt des Reaktionsgasausgangsgemischs mit der partiell zu oxidierenden Ausgangsverbindung.

In principle, the loading of the catalyst charge with the starting compound to be partially oxidized (propene, isobutene and / or tert-butanol (or its methyl ether)) can be adjusted by means of two adjusting screws:

• a) the load of the catalyst charge with reaction gas starting mixture; and or
• b) the content of the reaction gas starting mixture with the starting compound to be partially oxidized.

The According to the invention available annular Full catalysts are particularly suitable even if above 130 Nl / l · h loads of catalyst charge with the partially oxidized organic compound, the load setting especially via the aforementioned screw a).

Of the Propene fraction (iso-butene portion or tert-butanol portion (or its Methyl ether)) in the reaction gas starting mixture is usually (i.e., essentially independent of the load) 4 up to 20 vol.%, often 5 to 15 vol.%, or 5 to 12 vol.%, or 5 to 8% by volume (in each case based on the total volume).

Often one will have the process of those available with those as described annular full catalysts catalyzed partial oxidation (essentially independent of the load) at one Partially oxidized (organic) compound (eg propene): Oxygen: indifferent gases (including water vapor) Volume ratio in the reaction gas starting mixture of 1: (1.0 to 3.0) :( 5 to 25), preferably 1: (1.5 to 2.3) :( 10 to 20).

Under Indifferent gases (or inert gases) become such gases understood that in the course of the partial oxidation to at least 95 mol%, preferably at least 98 mol% chemically unchanged remain.

at the reaction gas starting mixtures described above can the indifferent gas is ≥ 20 vol.%, or ≥ 30 Vol .-%, or to ≥ 40 Vol .-%, or to ≥ 50 Vol .-%, or to ≥ 60 vol .-%, or to ≥ 70 vol .-%, or to ≥80% by volume, or to ≥90% by volume, or to ≥95 Vol .-% consist of molecular nitrogen.

At loads of the catalyst charge with the partially oxidized organic compound of ≥ 150 Nl / l · h, however, the concomitant use of inert diluent gases such as propane, ethane, methane, pentane, butane, CO ₂ , CO, water vapor and / or noble gases for the starting reaction gas mixture is recommended. In general, however, these inert gases and their mixtures can also be used at lower loads according to the invention of the catalyst charge with the organic compound to be partially oxidized. Also, cycle gas can be used as diluent gas. Cycle gas is understood to mean the residual gas which remains when the target compound is essentially selectively separated from the product gas mixture of the partial oxidation. It should be noted that the partial oxidations to acrolein or methacrolein with the available annular unsupported catalysts can only be the first stage of a two-stage partial oxidation to acrylic acid or methacrylic acid as the actual target compounds, so that the recycle gas then usually takes place only after the second stage. In the context of such a two-stage partial oxidation, the product mixture of the first stage as such, if appropriate after cooling and / or secondary oxygen addition, is generally fed to the second partial oxidation stage.

In the partial oxidation of propene to acrolein, using the available as described annular unsupported catalysts, a typical composition of the starting reaction gas mixture measured at the reactor inlet (regardless of the selected load) z. B. contain the following components: 6 to 6.5% by volume propene, 1 to 3.5 vol.% H ₂ O, 0.2 to 0.5 vol.% CO, 0.6 to 1.2% by volume CO ₂ , 0.015 to 0.04 vol.% acrolein, 10.4 to 11.3% by volume O ₂ and as residual amount ad 100% molecular nitrogen, or: 5.6 vol.% propene, 10.2% by volume Oxygen, 1.2% by volume CO _x , 81.3% by volume N ₂ and 1.4% by volume H ₂ O.

The former Compositions are particularly suitable for propene loads of ≥ 130 Nl / lh and the latter composition especially at propene loads <130 Nl / l · h, in particular ≤ 100 Nl / lh.

Suitable alternative compositions of the starting reaction gas mixture (regardless of the selected load) are those which have the following component contents: 4 to 25 vol.% propylene, 6 to 70 vol.% Propane, 5 to 60 vol.% H ₂ O, 8 to 65 vol.% O ₂ , and 0.3 to 20 vol.% H ₂ ; or 4 to 25 vol.% propylene, 6 to 70 vol.% Propane, 0 to 60 vol.% H ₂ O, 8 to 16 vol.% O ₂ , 0 to 20 vol.% H ₂ , 0 to 0.5 vol.% CO, 0 to 1.2% by volume CO ₂ , 0 to 0.04 vol.% acrolein, and as the remainder ad 100% by volume of substantially N ₂ ; or 50 to 80 vol.% Propane, 0.1 to 20 vol.% propylene, 0 to 10 vol.% H ₂ , 0 to 20 vol.% N ₂ , 5 to 15 vol.% H ₂ O, so much molecular oxygen that the molar ratio of oxygen content to propylene content is 1.5 to 2.5. or 6 to 9 vol.% propylene, 8 to 18% by volume molecular oxygen, 6 to 30 vol.% Propane, and 32 to 72 vol.% molecular nitrogen.

The reaction gas starting mixture may also be composed as follows: 4 to 15 vol.% propene, 1.5 to 30 vol.% (often 6 to 15% by volume) of water, ≥ 0 to 10% by volume (preferably ≥ 0 to 5% by volume) of propene, Water, oxygen and nitrogen of various components, so much molecular oxygen, that the molar ratio of molecular oxygen contained to molecular propene contained is 1.5 to 2.5 and the balance up to 100 vol .-% total amount of molecular nitrogen.

Another possible reaction gas starting mixture composition may include: 6.0% by volume propene, 60% by volume air and 34 vol.% H ₂ O.

Alternatively, reaction gas starting mixtures of the composition according to Example 1 of EP-A 990 636 , or according to Example 2 of EP-A 990 636 , or according to Example 3 of EP-A 1,106,598 , or according to Example 26 of EP-A 1,106,598 , or according to Example 53 of EP-A 1,106,598 be used.

Also suitable are the annular catalysts obtainable as described for the processes of DE-A 102 46 119 respectively. DE-A 102 45 585 ,

Further reaction gas starting mixtures which are suitable according to the invention can be in the following composition grid: 7 to 11 vol.% propene, 6 to 12 vol.% Water, ≥ 0 to 5 vol.% propene, water, oxygen and nitrogen different constituents, molecular oxygen enough that the molar ratio of oxygen contained to the molecular propene to be contained is 1.6 to 2.2, and the remaining amount is up to 100 vol% of the total amount of molecular nitrogen.

In the case of methacrolein as the target compound, the starting reaction gas mixture may in particular also as in DE-A 44 07 020 be composed described.

The Reaction temperature for the propene partial oxidation is when using the available as described annular Full catalysts often at 300 to 380 ° C. The the same applies in the case of methacrolein as the target compound.

Of the Reaction pressure is for the aforementioned partial oxidation usually at 0.5 or 1.5 to 3 or 4 bar (meant in this document, unless explicitly stated otherwise, Absolute pressure).

The total load of the catalyst charge with reaction gas starting mixture amounts to in the aforementioned partial oxidation typically 1000 to 10000 Nl / l · h, usually 1500 to 5000 Nl / l · h and often to 2000 to 4000 Nl / l · h.

As to be used in the starting reaction gas mixture propene are mainly polymer grade propene and chemical grade propene into consideration, as z. B. the DE-A 102 32 748 describes.

When Oxygen source is normally used air.

The partial oxidation in application of the annular unsupported catalysts obtainable as described can in the simplest case, for. B. be carried out in a one-zone Vielkontaktrohr fixed bed reactor, as him DE-A 44 31 957 , the EP-A 700 714 and the EP-A 700 893 describe.

Usually, in the aforementioned tube bundle reactors, the contact tubes are made of ferritic steel and typically have a wall thickness of 1 to 3 mm. Their inner diameter is usually 20 to 30 mm, often 21 to 26 mm. A typical contact tube length amounts to z. B. at 3.20 m. In terms of application, the number of catalyst tubes accommodated in the tube bundle container amounts to at least 5000, preferably to at least 1000. Often the number of catalyst tubes accommodated in the reaction container is 15000 to 35000. Tube bundle reactors having a number of contact tubes above 40000 tend to be the exception. Within the container, the contact tubes are normally distributed homogeneously, the distribution is suitably chosen so that the distance between the central inner axes of closest contact tubes (the so-called contact tube pitch) is 35 to 45 mm (see. EP-B 468 290 ).

The partial oxidation can, however, also be carried out in a multizone (eg "two-zone") multi-contact-tube fixed bed reactor, such as the DE-A 199 10 506 , the DE-A 103 13 213 , the DE-A 103 13 208 and the EP-A 1,106,598 especially at elevated loads of the catalyst charge with the partially oxidized organic compound recommend. A typical contact tube length in the case of a two-zone multi-contact fixed bed reactor is 3.50 m. Everything else is essentially as described in the single-zone multi-contact fixed bed reactor. Around the catalyst tubes, within which the catalyst feed is located, a heat exchange medium is guided in each tempering zone. As such are z. B. Melting of salts such as potassium nitrate, potassium nitrite, sodium nitrite and / or sodium nitrate, or of lower melting metals such as sodium, mercury and alloys of various metals. The flow rate of the heat exchange medium within the respective tempering zone is usually selected so that the temperature of the heat exchange medium from the point of entry into the temperature zone to the exit point from the temperature zone by 0 to 15 ° C, often 1 to 10 ° C, or 2 to 8 ° C, or 3 to 6 ° C increases.

The inlet temperature of the heat exchange medium, which, viewed over the respective temperature control, can be conducted in cocurrent or in countercurrent to the reaction gas mixture is preferably as in the publications EP-A 1,106,598 . DE-A 199 48 523 . DE-A 199 48 248 . DE-A 103 13 209 . EP-A 700 714 . DE-A 103 13 208 . DE-A 103 13 213 . WO 00/53557 . WO 00/53558 . WO 01/36364 . WO 00/53557 as well as the other writings cited in this document as prior art recommended. Within the tempering zone, the heat exchange medium is preferably guided in meandering fashion. In general, the multi-contact fixed-bed reactor also has thermal tubes for determining the gas temperature in the catalyst bed. Conveniently, the inner diameter of the thermo tubes and the diameter of the inner receiving sleeve for the thermocouple is chosen so that the ratio of heat of reaction evolving volume to heat dissipating surface is the same or only slightly different in thermal tubes and work tubes.

Of the Pressure loss should be related to working tubes and thermotubes to be the same GHSV, the same. A pressure loss similar to the thermal tube can by adding split catalyst to the catalyst bodies respectively. This compensation is expedient over the entire thermal tube length is homogeneous.

to Preparation of the catalyst charge in the catalyst tubes can, as already mentioned, only available as described annular unsupported catalysts or z. B. also largely homogeneous mixtures of available as described annular Vollkatalysatoren and no active material having, with respect heterogeneously catalyzed partial gas phase oxidation substantially inert behaving moldings are used. As materials for such inert moldings come z. B. porous or nonporous aluminas, silica, zirconia, Silicon carbide, silicates such as magnesium or aluminum silicate or Steatite (for example of the type C220 from CeramTec, DE).

The geometry of such inert shaped diluent bodies can in principle be arbitrary. That is, it can for example, spheres, polygons, solid cylinders or, like the shaped catalyst bodies, rings. Often one will choose as inert diluent moldings whose geometry corresponds to that of the catalyst molding to be diluted with them. However, the geometry of the shaped catalyst body can also be changed along the catalyst charge or shaped catalyst bodies of different geometry can be used in substantially homogeneous mixing. In a less preferred procedure, the active composition of the catalyst molding can also be changed along the catalyst charge.

All Generally, as already mentioned, the catalyst feed designed with advantage such that the volume-specific (i.e., the Normalized to the unit of volume) activity in the flow direction the reaction gas mixture either remains constant or increases (continuous, erratic or stepped).

A Reduction in volume-specific activity may occur in simple way z. B. be achieved by giving a basic amount of uniformly produced according to the invention annular unsupported catalysts with inert diluent bodies diluted homogeneously. The higher the proportion of the diluent molding selected The lower is the one in a given volume of the feed contained active mass or catalyst activity. A reduction but can also be achieved by the geometry of the According to the invention available annular Full catalysts changed so that in the unit total ring volume (including ring opening) amount of active mass becomes smaller.

For the heterogeneously catalyzed Gasphasenpartialoxidationen with the annular unsupported catalysts available as described For example, the catalyst feed is preferably either on the entire length uniformly designed with only one full catalyst ring or how follows structured. At the reactor entrance will be on a length from 10 to 60%, preferably 10 to 50%, more preferably 20 to 40% and most preferably 25 to 35% (i.e., e.g. Length from 0.70 to 1.50 m, preferably 0.90 to 1.20 m), each of the total length of the catalyst charge, a Substantially homogeneous mixture of obtainable according to the invention annular unsupported catalyst and inert diluent molding (both preferably being substantially the same geometry having), wherein the weight fraction of the diluent molding (The mass densities of shaped catalyst bodies and of shaped diluents usually differ only slightly) normally 5 to 40 wt .-%, or 10 to 40 wt .-%, or 20 to 40 wt .-%, or 25 to 35 wt .-% is. Following this first Loading section is then advantageous to the end the length of the catalyst feed (i.e., e.g. a length of 1.00 to 3.00 m or 1.00 to 2.70 m, preferably 1.40 to 3.00 m, or 2.00 to 3.00 m) either one diluted only to a lesser extent (than in the first section) Batch of the available as described annular Full catalyst, or, most preferably, a sole (undiluted) bed of the same annular unsupported catalyst, which has also been used in the first section. Naturally can also be a constant dilution over the entire feed to get voted. Also, in the first section only with one According to the invention available annular Full catalyst of low, based on its space requirement, active mass density and in the second section with an inventively available annular full catalyst with high, on its space requirements referred to, be charged active mass density (eg 6.5 mm × 3 mm × 4.5 mm [A × H × I] in the first section, and 5 × 2 × 2 mm in the second section).

All in all be in an annular with the available as described Full catalysts carried out as catalysts partial oxidation for the production of acrolein or methacrolein, the catalyst charge, the reaction gas starting mixture, the load and the reaction temperature usually chosen so that when a single pass of the reaction gas mixture through the catalyst feed a conversion the partially oxidized organic compound (propene, isobutene, tert-butanol or its methyl ether) of at least 90 mol%, or 92 mol%, preferably of at least 94 mol% results. The selectivity the formation of acrolein or methacrolein is regularly ≥ 80 mol%, or ≥ 85 mol%. In natural This way, the lowest possible hotspot temperatures are possible sought.

All in all condition the annular available as described Vollkatalysatoren an increased selectivity of Target product formation.

Finally, it should be noted that the annular unsupported catalysts obtainable as described also have an advantageous fracture behavior during reactor filling. Her pressure loss behavior is advantageous. Incidentally, the annular unsupported catalysts obtainable as described are quite generally suitable as catalysts with increased selectivity for gas-phase catalytic partial oxidations of organic compounds such as lower (eg 3 to 6 (ie 3, 4, 5 or 6) carbon atoms) alkanes (US Pat. in particular propane), alkanols, alkanals, alkenes and alkenals to olefinically unsaturated adhesions and / or carboxylic acids, and the corresponding nitriles (ammoxidation, especially of propene to acrylonitrile and 2-methylpropene or tert-butanol (or its methyl ether) to methacrylonitrile) and for gas-phase catalytic oxidative dehydrogenation of organic compounds (eg., 3, 4, 5, or 6 C atoms containing).

• a) [Bi₂W₂O₉ × 2WO₃]_0,5[Mo₁₂Co_5,5Fe_2,94Si_1,59K_0,08O_x]₁;
• b) Mo₁₂Ni_6,5Zn₂Fe₂Bi₁P_0,0065K_0,06O_x·10SiO₂;
• c) Mo₁₂Co₇Fe_2,94Bi_0,6Si_1,59K_0,08O_x;
• d) wie Multimetalloxid II-Vollkatalysator gemäß Beispiel 1 der DE-A 197 46 210 ; und
• e) Wie Beispiel 1c aus der EP-A 015 565 .

For the process of propylene partial oxidation to acrolein particularly advantageous stoichiometries are:

• a) [Bi ₂ W ₂ O ₉ x 2WO ₃ ] _0.5 [Mo ₁₂ Co _5.5 Fe _2.94 Si _1.59 K _0.08 O _x ] ₁ ;
• b) Mo ₁₂ Ni _6.5 Zn ₂ Fe ₂ Bi ₁ P _0.0065 K _0.06 O _x 10SiO ₂ ;
• c) Mo ₁₂ Co ₇ Fe _2.94 Bi _0.6 Si _1.59 K _0.08 O _x ;
• d) as Multimetalloxid II full catalyst according to Example 1 of DE-A 197 46 210 ; and
• e) As Example 1c from the EP-A 015 565 ,

The bismuth content of the active compositions described can also be as in the DE-A 100 63 162 be set described. In this case, a solution or suspension is produced from starting compounds of the elemental constituents of the desired active composition, which indeed contains the required for the preparation of the active mass of Bi different elemental constituents, but only a subset of the Bi required for the preparation of the active composition containing the solution or suspension Obtained a dried dry mass and additionally required for the preparation of the active mass residual amount of Bi in the form of a starting compound of the Bi as in DE-A 100 63 162 incorporated into this dry mass to obtain a moldable mixture (eg., As in the example of DE-A 100 63 162 ), the moldable mixture in accordance with the invention (ie after addition of molding and optionally reinforcing aids) to form an annular Vollkatalysatorformkörper and this by thermal treatment (eg., As in the example of DE-A 100 63 162 ) into the desired annular unsupported catalyst. The stoichiometries (in particular of the working examples) and thermal treatment conditions of this (aforementioned) document are likewise particularly suitable for the propylene partial oxidation to acrolein. This applies in particular to the stoichiometry Mo ₁₂ Bi _1.0 Fe ₃ Co ₇ Si _1.6 K _0.08 .

The commissioning of a fresh catalyst feed with available as described annular unsupported catalysts as described in the DE-A 10337788 described described. Typically, the activity and selectivity of target product formation initially increase with the service life of the catalyst feed. This formation can be accelerated by carrying it out at substantially constant conversion under increased loading of the catalyst charge with reaction gas starting mixture and after largely completed formation takes back the load to its target value.

Furthermore, the present invention particularly comprises a process for the preparation of annular shaped catalyst bodies with curved and / or non-curved end face of the rings, whose active composition has a stoichiometry of the general formula IV, Mo ₁₂ P _a V _b X _c ¹ X _d ² X _e ³ Sb _f Re _g S _h O _n (IV) in which variables have the following meaning:
X ¹ = potassium, rubidium and / or cesium,
X ² = copper and / or silver,
X ³ = cerium, boron, zirconium, manganese and / or bismuth,
a = 0.5 to 3,
b = 0.01 to 3,
c = 0.2 to 3,
d = 0.01 to 2,
e = 0 to 2,
f = 0.01 to 2,
g = 0 to 1,
h = 0.001 to 0.5 and
n = a number determined by the valence and frequency of the elements other than oxygen in IV,
and whose annular geometry corresponds to that of the already described annular shaped catalyst bodies having active masses of a stoichiometry of the general formula (I), (II), or (III).

Prefers are active masses IV in which h is 0.03 to 0.5.

Particularly preferred stoichiometry of the general formula IV are those of the embodiments B1 to B15 from the EP-A 467 144 and even if these exemplary active masses no K and / or no re included.

The aforementioned EP-A 467 144 also describes the preparation of such annular shaped catalyst bodies and their use as catalysts for the heterogeneously catalyzed gas phase partial oxidation of methacrolein to methacrylic acid. These descriptions are also true in the context given in the present application, apart from the fact that in the preparation of the annular shaped catalyst body according to the invention to be used graphite is to be used as a lubricant.

In other words, annular shaped catalyst bodies having active masses of general stoichiometry IV can be prepared by dissolving and / or purifying suitable salts of constituent elemental constituents, optionally at elevated temperature and with the addition of acids or bases, in an aqueous medium Suspend finely divided and, to avoid unwanted oxidation processes, if necessary under inert gas, mixes, the mixture dries (eg, evaporated or spray-dried), the resulting, finely divided form or finely divided form dry mass the graphite required according to the invention and optionally other of the mentioned Forming aids and reinforcing agents added, the resulting finely divided mass to the desired ring geometry (compacted) and the resulting Katalysatorvorläuferformkörper then thermally treated. The thermal treatment is preferably carried out at temperatures of from 180 to 480 ° C., more preferably at temperatures of from 250 to 450 ° C. The thermal treatment can be carried out under the gas atmospheres already described. By way of example, mention may be made again of flowing air, flowing inert atmosphere (for example N ₂ , or CO ₂ , or noble gases) or vacuum. The thermal treatment can be carried out in several temperature stages and / or in different atmospheres. So z. B. in a first stage at 200 to 260 ° C in air, in a second stage at 420 to 460 ° C in nitrogen and in a third stage at 350 to 410 ° C are again thermally treated in air. As a rule, flowing air is the preferred atmosphere for the thermal treatment.

Furthermore This applies in the production of annular shaped catalyst bodies the active compounds (I), (II) and (III) said here in corresponding Way, but with the difference that here the increased Side crush strengths for the annular unsupported catalyst precursor moldings to be favoured.

That is, z. B. preferred drying method for the aqueous solution or suspension of the sources of the elemental constituents of the desired active composition is the spray drying. The resulting spray powder with a particle diameter d ₅₀ between 10 to 50 microns is according to the invention advantageously and according to the invention advantageously after the addition of finely divided graphite according to the invention as auxiliaries, intermediately compacted to coarsen the powder. Preferably, the Zwischenkompaktierung here on particle diameter of 100 to 2000 .mu.m, preferably from 150 to 1500 .mu.m and more preferably from 400 to 1000 microns. Subsequently, the actual shaping takes place on the basis of the coarsened powder, it being possible once again to add finely divided graphite according to the invention (and optionally further shaping and / or reinforcing assistants) if necessary beforehand. The statements made in the preparation of the annular shaped catalyst bodies of the active compositions (I), (II) and (III) to the lateral compressive strengths apply analogously here.

In the described preparation of annular shaped catalyst bodies of active compounds of the general formula IV antimony is usually used as antimony trioxide, rhenium z. B. as rhenium (VII) oxide, molybdenum preferably as the ammonium salt of molybdenum or phosphomolybdic acid, boron z. As boric acid, vanadium usually as ammonium vanadate or vanadium oxalate, phosphorus with advantage as ortho-phosphoric acid or di-ammonium phosphate, sulfur z. As ammonium sulfate and the cationic metals are usually used as nitrates, oxides, hydroxides, carbonates, chlorides, formates, oxalates and / or acetates or their hydrates. The preferred ring geometry of the finished shaped catalyst article here is the geometry 7 mm × 7 mm × 3 mm (outer diameter × height × inner diameter). The catalytic gas phase oxidation of methacrolein to methacrylic acid using the annular shaped catalyst bodies obtainable as described can be carried out in a manner known per se, for. B. in the EP-A 467 144 described manner done. The oxidant oxygen may, for. B. in the form of air, but also in pure form. Due to the high heat of reaction, the reactants are preferably diluted with inert gases such as N ₂ , CO, CO ₂ and / or with steam. Preferably, in a methacrolein: oxygen: water vapor: inert gas ratio of 1: (1 to 3) :( 2 to 20) :( 3 to 30), particularly preferably 1: (1 to 3) :( 3 to 10): (7 to 18) worked. The proportion of methacrolein in the reaction gas starting mixture is usually 4 to 11, often 4.5 to 9 vol .-%. The oxygen content is preferably limited to ≤ 12.5% by volume in order to avoid explosive mixtures. This is particularly preferably achieved by recycling a partial stream of the offgas separated from the reaction product. Incidentally, the gas phase partial oxidation to methacrylic acid is typically carried out at total space loadings of the fixed catalyst bed of 600 to 1800 Nl / l · h, or at Methacroleinbelastungen of 40 to 100 Nl / l · h. The reactor used is generally a tube bundle reactor. Reaction gas and salt bath can be conducted over the reactor both in cocurrent and in countercurrent. The salt bath itself is normally passed through the reactor in meandering form. Preferred graphite for the production of annular shaped catalyst bodies from active materials of general stoichiometry IV is Asbury 3160 and / or Asbury 4012.

The inventive method further comprises in particular a process for the preparation of annular shaped catalyst bodies with curved and / or non-curved face of the rings whose active composition is a vanadium, phosphorus and oxygen-containing multielement oxide, and which are catalysts for the heterogeneously catalyzed gas phase oxidation of at least one hydrocarbon at least four carbon atoms (especially n-butane, n-butenes and / or benzene) to maleic anhydride are suitable. The stoichiometry of the Multielementoxidmasse can then z. B. be one of the general formula V, V ₁ P _b Fe _c X ¹ _d X ² _e O _n (V), in which the variables have the following meaning:
X ¹ = Mo, Bi, Co, Ni, Si, Zn, Hf, Zr, Ti, Cr, Mn, Cu, B, Sn and / or Nb,
X ² = K, Na, Rb, Cs and / or Tl,
b = 0.9 to 1.5,
c = 0 to 0.1,
d = 0 to 0.1,
e = 0 to 0.1, and
n = a number determined by the valency and frequency of the non-oxygen elements in V.

The production of corresponding annular shaped catalyst bodies is in the WO 03/078310 described with the addition of unspecified graphite as a molding aid. All versions of the WO 03/078310 and all in the WO 03/078310 addressed catalysts also have load capacity and in the WO 03/078310 Applicability, if applicable, in the WO 03/078310 disclosed manufacturing measures are maintained, and the co-used in the manufacture graphite is replaced by weight-identical amounts of graphite according to the invention. However, the selectivity of target product formation is increased. Ie. Also in the aforementioned case of vanadium, phosphorus and oxygen-containing annular multielement oxide catalysts, the advantages according to the invention appear. This applies in particular to all embodiments of the WO 03/078310 ,

• a) Umsetzung einer fünfwertigen Vanadiumverbindung (z. B. V₂O₅) mit einem organischen, reduzierenden Lösungsmittel (z. B. iso-Butanol) in Gegenwart einer fünfwertigen Phosphorverbindung (z. B. Ortho- und/oder Pyrophosphorsäure) unter Erwärmen auf 75 bis 205°C, bevorzugt auf 100 bis 120°C;
• b) Abkühlen des Reaktionsgasgemisches auf vorteilhaft 40 bis 90°C;
• c) Zugabe von Eisen(III)phosphat;
• d) Erneutes Erwärmen auf 75 bis 205°C, bevorzugt 100 bis 120°C;
• e) Isolierung der gebildeten festen Vanadium-, Phosphor-, Eisen- und Sauerstoff enthaltenden festen Vorläufermasse (z. B. durch Filtrieren);
• f) Trocknung und/oder thermische Vorbehandlung der Vorläufermasse (gegebenenfalls bis zu beginnender Vorformierung durch Wasserabspaltung aus der Vorläufermasse);
• g) Erfindungsgemäße Zugabe von Graphit und Formgebung durch Überführung in eine beispielsweise kugelförmige, ringförmige oder zylinderförmige Struktur; h) Thermische Behandlung der gebildeten Katalysatorvorläuferformkörper durch Erhitzen in einer Atmosphäre, welche Sauerstoff, Stickstoff, Edelgase, Kohlendioxid, Kohlenmonoxid und/oder Wasserdampf enthält, z. B. wie in der WO 03078310 auf Seite 20, Zeile 16 bis Seite 21, Zeile 35 beschrieben.

The above for the vanadium, phosphorus and oxygen containing multimetal oxide catalysts of WO 03/078310 and their use applies in a similar way to those of WO 01/68245 as well as for those of DE-A 10 2005 035 978 , The latter are according to the invention thus produced as follows:

• a) reacting a pentavalent vanadium compound (eg V ₂ O ₅ ) with an organic, reducing solvent (eg isobutanol) in the presence of a pentavalent phosphorus compound (eg ortho and / or pyrophosphoric acid) with heating at 75 to 205 ° C, preferably at 100 to 120 ° C;
• b) cooling the reaction gas mixture to advantageously 40 to 90 ° C;
• c) addition of iron (III) phosphate;
• d) reheating to 75 to 205 ° C, preferably 100 to 120 ° C;
• e) isolating the formed solid vanadium, phosphorus, iron and oxygen-containing solid precursor composition (eg by filtration);
• f) drying and / or thermal pretreatment of the precursor composition (if appropriate until incipient preformation by dehydration from the precursor composition);
• g) addition of graphite and shaping according to the invention by conversion into a, for example, spherical, annular or cylindrical structure; h) Thermal treatment of the formed catalyst precursor moldings by heating in an atmosphere containing oxygen, nitrogen, noble gases, carbon dioxide, carbon monoxide and / or water vapor, for. B. as in the WO 03078310 on page 20, line 16 to page 21, line 35 described.

The process according to the invention furthermore comprises, in particular, processes for the preparation of novel, e.g. B. spherical, fully cylindrical or annular shaped catalyst bodies with curved and / or non-curved end face of the rings whose active material is a Mo, V and at least one of the elements Te and Sb containing multimetal, as z. For example, the scriptures EP-A 962 253 . DE-A 101 22 027 . EP-A 608 838 . DE-A 198 35 247 . EP-A 895 809 . EP-A 1 254 709 . EP-A 1 192 987 . EP-A 1 262 235 . EP-A 1 193 240 . JP-A 11-343261 . JP-A 11-343262 . EP-A 1 090 684 . EP-A 1 301 457 . EP-A 1 254 707 . EP-A 1 335 793 . DE-A 100 46 672 . DE-A 100 34 825 . EP-A 1 556 337 . DE-A 100 33 121 . WO 01/98246 . EP-A 1 558 569 describe.

Often the aforementioned multimetal oxide materials still contain the element Nb. The aforementioned multimetal oxide catalysts are useful inventive production for all performed heterogeneously in the aforementioned publications catalyzed gas phase reactions. These are in particular the heterogeneous catalyzed partial gas phase oxidation of propane to acrylic acid and from acrolein to acrylic acid, from methacrolein to methacrylic acid and from iso-butane to methacrylic acid.

Finally, it should be noted at this point that shaped catalyst bodies produced according to the invention do not necessarily have to be used as such as catalysts for heterogeneously catalyzed gas phase reactions. Rather, they can be subjected to grinding and, after classifying the resulting finely divided material with the aid of a suitable liquid binder applied to the surface of a suitable carrier body. After drying or immediately after application of the active material shell on the support body, the resulting coated catalyst can be used as a catalyst for heterogeneously catalyzed gas phase reactions, as z. B. the DE-A 101 22 027 describes.

In summary, it should again be noted that the catalyst moldings obtainable according to the invention are outstandingly suitable as catalysts for heterogeneously catalyzed reactions in the gas phase with increased selectivity of the target product formation. These gas phase reactions include, in particular, the partial oxidations of organic compounds, the partial ammoxidations of organic compounds and the oxydehydrogenation of organic compounds. As partial heterogeneously catalyzed oxidation of organic compounds, especially in the DE-A 10 2004 025 445 mentioned in consideration. Examples include again the reaction of propylene to acrolein and / or acrylic acid (cf., for example. DE-A 23 51 151 ), the reaction of tert-butanol, isobutene, isobutane, isobutyraldehyde or the methyl ether of the tert-butanol to methacrolein and / or methacrylic acid (cf. DE-A 25 26 238 . EP-A 092 097 . EP-A 58927 . DE-A 41 32 263 . DE-A 41 32 684 and DE-A 40 22 212 ), the conversion of acrolein to acrylic acid, the conversion of methacrolein to methacrylic acid (cf., for example, the DE-A 25 26 238 ), the reaction of o-xylene, p-xylene or naphthalene to phthalic anhydride (cf. EP-A 522 871 ) or the corresponding acids and the reaction of butadiene to maleic anhydride (cf. DE-A 21 06 796 and DE-A 16 24 921 ), the reaction of n-butane to maleic anhydride (cf. GB-A 1 464 198 and GB-A 1 291 354 ), the conversion of indenes to z. For example anthraquinone (cf. DE-A 20 25 430 ), the reaction of ethylene to ethylene oxide or of propylene to propylene oxide (cf. DE-AS 12 54 137 . DE-A 21 59 346 . EP-A 372 972 . WO 89/07101 . DE-A 43 11 608 and Beyer, Textbook of Organic Chemistry, 17th Edition (1973), Hirzel Verlag, Stuttgart, p. 261 ), the reaction of propylene and / or acrolein to acrylonitrile (cf., for example DE-A 23 51 151 ), the conversion of isobutene and / or methacrolein to methacrylonitrile (ie, the term partial oxidation should, as already stated, in this document also include partial ammoxidation, ie a partial oxidation in the presence of ammonia), the oxidative Dehydrogenation of hydrocarbons (cf. DE-A 23 51 151 ), the conversion of propane to acrylonitrile or to acrolein and / or acrylic acid (cf. DE-A 101 31 297 . EP-A 1 090 684 . EP-A 608 838 . DE-A 100 46 672 . EP-A 529 853 . WO 01/96270 and DE-A 100 28 582 ), the reaction of iso-butane to methacrolein and / or methacrylic acid, such as the reactions of ethane to acetic acid, of ethylene to ethylene oxide, of benzene to phenol and of hydrocarbons having 4 carbon atoms to the corresponding butanediols or to butadiene.

Of course However, it can also be a heterogeneous in the gas phase reaction catalyzed hydrogenation or heterogeneously catalyzed dehydrogenation act organic compounds.

Examples B and Comparative Examples V

A) Production of annular Full catalyst moldings with the following stoichiometry the active composition and using various graphites as molding aids:

• [Bi ₂ W ₂ O ₉ • 2WO ₃ ] _0.48 [Mo ₁₂ Co _5.4 Fe _3.1 Si _1.5 Ko _0.08 O _x ] ₁ .

1. Preparation of a starting material 1

In 780 kg of an aqueous nitrate of bismuth nitrate at 25 ° C. (11.2% by weight of Bi; free nitric acid 3 to 5% by weight; bulk density: 1.22 to 1.27 g / ml, prepared with nitric acid from Wis Purity metal: Sidech SA, 1495 Tilly, Belgium, purity:> 99.997% by weight of Bi, <7 mg / kg of Pb, <5 mg / kg of Ni, Ag, Fe, <3 mg / kg of Cu, Sb and <1 mg / kg Cd, Zn) at 25 ° C within 20 min portionwise 214.7 kg of a 25 ° C having tungstic acid (74.1 wt .-% W, HC Starck, D-38615 Goslar, purity> 99 , 9 wt .-% WO ₃ after annealing at 750 ° C, 0.4 microns <d ₅₀ <0.8 microns stirred (70 U / min). The resulting aqueous mixture was then stirred for 3 h at 25 ° C and then spray-dried.

The spray drying was carried out in a rotary hot air spray counter at a gas inlet temperature of 300 ± 10 ° C, a gas outlet temperature of 100 ± 10 ° C, a disk speed of 18000 U / min and a throughput of 200 l / h. The resulting spray powder, whose grain size was substantially between 5 and 30 μm and which had a loss on ignition of 12.8% by weight (glowing at 600 ° C. under air for 3 h), was then admixed with 16.7% by weight ( based on the powder) pasted to 25 ° C water in a kneader (20 U / min) for 30 min and extruded by means of an extruder (torque: ≤ 50 Nm) to strands of diameter 6 mm. These were cut into 6 cm sections on a 3-zone belt dryer with a residence time of 120 minutes per zone at temperatures of 90-95 ° C (zone 1), 115 ° C (zone 2) and 125 ° C (zone 3) dried in air and then thermally treated at a temperature in the range of 830 ° C. (calcined, in the rotary kiln with air flow (0.3 mbar vacuum, 1.54 m ³ internal volume, 200 Nm ³ / h air, 50 kg / h extrudate, Speed: 1 rpm)). Essential in the exact setting of the calcination temperature is that it has to be oriented on the desired phase composition of the calcination product. The phases WO ₃ (monoclinic) and Bi ₂ W ₂ O ₉ (orthorhombic) are desired, the presence of γ-Bi ₂ WO ₆ (Russellite) is undesirable. If, therefore, after the calcination, the compound γ-Bi ₂ WO ₆ still be detectable on the basis of a reflection in the X-ray powder diffractogram at a reflection angle of 2Θ = 28.40 (CuKα radiation), the preparation must be repeated and the calcination temperature within the specified temperature range or increase the residence time at the same calcination temperature until the disappearance of the reflex is achieved. The preformed calcined mixed oxide obtained in this way was ground with a BQ500 bipolar mill at 2500 rpm, so that the d ₅₀ value was 2.45 μm (d ₁₀ = 1.05 μm, d ₉₀ = 5.92 μm) and the BET Surface 0.8 m ² / g was.

The millbase was then in portions of 5 kg in an Eirich intensive mixer (type R02, filling volume: 3-5 l, 1.9 kW, Maschinenfabrik Gustav Eirich GmbH & Co KG, D-74736 Hardheim) with counter-rotating to the plate cutter heads ( plate speed: 50 r / min, tachometer heads. 2500 rev / min) within 5 (min homogeneous particulate with 0.5 wt .-% (based on the material to be ground) SiO ₂ from Degussa type Sipernat ^® D17 bulk density 150 g / l; d ₅₀ value of the SiO ₂ particles (laser diffraction according to ISO 13320-1) was 10 μm, the specific surface area (nitrogen adsorption according to ISO 5794-1, Annex D) was 100 m ² / g).

2. Preparation of a starting material 2

A solution A was prepared by stirring at 60 ° C with stirring (70 rpm) to 660 l of water at 60 ° C for one minute, 1.075 kg of an aqueous potassium hydroxide solution (47.5%) having a temperature of 60 ° C Wt .-% KOH) and then with a metering rate of 600 kg / h 237.1 kg ammonium heptamolybdate tetrahydrate (white crystals with a grain size d <1 mm, 81.5 wt .-% MoO ₃ , 7.0-8, 5% by weight of NH ₃ , at most 150 mg / kg of alkali metals, HC Starck, D-38642 Goslar) and the resulting slightly turbid solution was stirred at 60 ° C. for 60 minutes.

A solution B was prepared by mixing at 60 ° C in 282.0 kg of a 60 ° C aqueous cobalt (II) nitrate solution (12.5 wt .-% Co, prepared with cobalt metal nitric acid from the company MFT Metals & Ferro-Allogs Trading GmbH, D-41747 Viersen, purity,> 99.6 wt.%, <0.3 wt.% Ni, <100 mg / kg Fe, <50 mg / kg Cu) 142.0 kg of a 60 ° C. iron (III) nitrate nonahydrate melt (13.8% by weight of Fe, <0.4% by weight of alkali metals, with stirring (70 rpm)). <0.01% by weight of chloride, <0.02% by weight of sulfate, Dr. Paul Lohmann GmbH, D-81857 Emmerthal). The mixture was then stirred while maintaining the 60 ° C for 30 minutes. Then, while maintaining the 60 ° C, the solution B was drained into the initially charged solution A and stirred at 60 ° C for a further 15 minutes. Subsequently, the resulting aqueous mixture 19.9 kg of a silica gel from the company. Du Pont Ludox type (49.1 wt .-% SiO ₂ , density: 1.29 g / ml, pH 8.5 to 9.5, alkali content 0.5 wt .-% maximum) was added and then stirred for a further 15 minutes at 60 ° C.

The mixture was then spray-dried in a rotary disk spray tower in hot air counterflow (gas inlet temperature: 350 ± 10 ° C., gas outlet temperature: 140 ± 5 ° C., disk speed: 18000 rpm). The resulting spray powder had a loss on ignition of 31.5 wt .-% (3 hours at 600 ° C under air glow) and a d ₅₀ of 19.7 microns (d ₁₀ = 3.19 microns, d ₉₀ = 51.49 microns ) on.

3. Preparation of the Multimetalloxidkatalysatorformkörper

The starting material 1 was mixed with the starting material 2 in the for a multimetal oxide of the stoichiometry [Bi ₂ W ₂ O ₉ • 2WO ₃ ] _0.48 [Mo ₁₂ Co _5.4 Fe _3.1 Si _1.5 K _0.08 O _x ] ₁ required quantities (total quantity: 3 kg) in an Eirich intensive mixer (type R02, filling volume: 3-5 l, power: 1.9 kW, Maschinenfabrik Gustav Eirich GmbH & Co. KG, D-74736 Hardheim) with cutter heads rotating in opposite directions to the plate (Speed plate: 50 rpm, speed cutter heads: 2500 rev / min) within 5 min homogeneously mixed.

Based on the aforementioned total mass were doing this in a Rhönradmischer (Wheel diameter: 650 mm, drum volume: 5 l) in addition 1 wt .-% of the respective graphite within 30 min at one speed homogeneously mixed in at about 30 rpm. The resulting mixture was then in a laboratory calender with 2 counter-rotating steel rollers compacted at a pressure of 9 bar and through a sieve with a Mesh size of 0.8 mm pressed. The resulting Kompaktat had a hardness of 10 N and a substantially uniform one Grain size of ≥ 0.4 mm and ≤ 0.8 mm.

The Kompaktat was then in a Rhönradmischer (Wheel diameter: 650 mm, drum volume: 5 l) at one speed of about 30 rpm within 30 minutes with, based on Weight, another 2.5 wt .-% of the same graphite mixed and then in a Kilian rotary (9-fold tableting machine) of the type S100 (Kilian, D-50735 Cologne) under a nitrogen atmosphere to annular unsupported catalyst precursor bodies geometry (5 × 3 × 2 mm, A (outer diameter) × H (Height) × I (inner diameter)) with a side crushing strength of 20 ± 1 N compressed (filling height: 7.5-9 mm, pressing force: 3.0-3.5 kN).

to final thermal treatment were each 1000 g of each prepared Vollkatalysatorvorläuferformkörper evenly distributed on side by side 4 grids with a square base of each 150 mm × 150 mm (dump height: approx. 15 mm) in a with 1000 Nl / h air flowed through convection oven (company Heraeus Instruments GmbH, D-63450 Hanau, type: K 750/2) initially with a heating rate of 80 ° C / h from room temperature (25 ° C) heated to 185 ° C. This temperature was for Maintained for 1 h and then with a heating rate of 48 ° C / h increased to 225 ° C. The 225 ° C were for 2 h before being heated at a rate of 120 ° C./h, was increased to 270 ° C. This temperature was also Maintained for 1 h before, at a heating rate of 60 ° C / h, was increased to 464 ° C. This final temperature was held for 10 hours. After that, it was brought to room temperature cooled.

4. Testing the with the different ones Graphite each obtained Vollkatalysatorformkörper for the heterogeneously catalyzed partial oxidation of propene to acrolein

A reaction tube (V2A steel, 21 mm outer diameter, 3 mm wall thickness, 15 mm inner diameter, length 120 cm) was charged from top to bottom in the flow direction as follows: Part 1: approx. 30 cm in length 40 g steatite balls with a diameter of 1.5 to 2.0 mm as pre-filling. Section 2: about 70 cm in length catalyst charge with 100 g of the produced under 3 annular unsupported catalyst.

The Temperature control of the reaction tube was carried out by means of a nitrogen bubbled salt bath.

The reactor was continuously charged with a feed gas mixture (mixture of air, polymer grade propylene and nitrogen) of the composition: 5 vol.% propene, 9.5 vol.% Oxygen and as residual amount up to 100% by volume N ₂ charged, wherein the load of the reaction tube with feed gas mixture 100 Nl / h (5 Nl / h propene) was and the thermostating of the reaction tube by varying the salt bath temperature T _S (° C) so he followed that the propene conversion U (mol%) was continuously about 95 mol% with a single pass of the feed gas mixture through the reaction tube.

• a: Graphite der Firma Timcal Ltd., 6743 Bodio, Schweiz
• b: Graphite der Firma Asbury Graphite Mills, Inc. New Jersey 08802, USA

The graphites used and their particle properties were: graphite d ₁₀ (μm) d ₅₀ (μm) d ₉₀ (μm) O _G (m ² / g) V1 Timrex HSAG 100 ^a 3.3 13.1 78.4 121 V2 Asbury 230U ^b 4.8 14.5 40.6 6.2 V3 Timrex T44 ^a 6.4 20.8 56.8 6.5 B1 Asbury 3160 ^b 37.0 123 259 1.6 B2 Asbury 4012 ^b 87.6 166 270 1.7

• a: Graphite from Timcal Ltd., 6743 Bodio, Switzerland
• b: Graphite from Asbury Graphite Mills, Inc. New Jersey 08802, USA

The various graphites used also had the following properties (an indent means that no property determination was carried out): graphite Ash content (wt.%) T _i (° C) T _m ° (C) V1 V1 - - - V2 V2 0.3 - - V3 V3 0.1 505 670 B1 B1 0.7 505 700 B2 B2 0.2 550 745

1 shows for the different graphites used the respective particle diameter distribution (laser, Malvern).

there the abscissa shows the diameter [μm] in logarithmic Scale. The ordinate shows the volume fraction of the respective gene Graphite, which has the respective diameter or a smaller diameter [Vol .-%].

• -⎕- V3
• 
  V2
• -O- V1
• -•- B1, und
• -+- B2

Where:

• -⎕- V3
• 
  V2
• -O- V1
• - • - B1, and
• - + - B2

Of the Ash content gives a complete combustion of the graphite remaining oxide residue (in Wt .-%, based on the weight of the burned amount of graphite).

The following table shows the total pore volume V (cm ³ / g), the specific surface O (m ² / g), the pore diameter d ^max (μm) of the pores, which are the largest in their total number, for the shaped catalyst bodies obtained using the various graphites percent contribution to the total pore volume V, the amount of graphite (calculated as pure carbon) Δm (wt.% based on the amount of graphite contained in 100 catalyst precursor moldings) which vanishes during thermal treatment of these catalyst precursor moldings therefrom, which for the propylene conversion is 95 moles -% when used as a catalyst for the described partial oxidation of propene to acrolein salt bath temperature required T _s (° C), (each determined after an operating time of 60 h) selectivity S ^A acrolein formation (mol%) as well as for the Case of a subsequent partial oxidation of the acrolein formed to acrylic acid wichti the sum of the selectivity S ^{A of} the acrolein formation and the selectivity S ^{AS of} the formation of acrylic acid by-products (S ^A + S ^AS , mol%): used graphite Dm V O d ^max T _S S ^A S ^A + S ^AS V1 57 0.268 6.67 0.224 332 87.3 94.5 V2 20 0,267 6.11 0,250 327 87.8 94.5 V3 23 0,275 6.64 0.259 332 88.6 95.0 B1 11 0.261 6.28 0.264 336 88.9 95.4 B2 11 0.249 5.86 0,273 331 89.2 95.4

The 2 to 6 In addition, the pore distribution of the unsupported catalyst bodies obtained with the various graphites (V1 → 2 ; V2 3 ; V3 → 4 ; B1 → 5 ; B2 → 6 ). In each case the pore diameter in the logarithmic scale in μm is plotted on the abscissa. On the left ordinate the logarithm of the differential contribution in ml / g of the respective pore diameter to the total pore volume is plotted (curve +). The maximum indicates the pore diameter d ^{max of} those pores which make the largest contribution to the total pore volume in percent. On the right ordinate in ml / g, the integral is plotted over the individual contributions of the individual pore diameters attributable pores to the total pore volume (curve O). The endpoint is the total pore volume.

at a preparation of the produce as described above Catalyst molding on an industrial scale In the manufacturing section "3.", it is substantially make the following changes:

Mix:

• Eirich Intensive Mixer (Maschinenfabrik Gustav Eirich GmbH Co KG, D-74736 Hardheim) with rotating cutter heads (speed: 3000 rpm, mixing time: 25 min).

compacting:

• Kompaktor K200 / 100 with concave, serrated smooth rollers (Gap width: 2.8 mm, mesh width: 1.0 mm, mesh size undersize: 400 μm, Pressing force: 75 kN, screw speed: <70 rpm, Hosokawa Bepex GmbH, D-74211 Leingarten).

Tabletting:

• Kilian rotary machine (tableting machine) of the type R × 73 (pressing force: 3-15 kN, Messrs. Kilian, D-50735 Cologne).

calcination:

Instead of carrying out the thermal treatment as described, it can also be used as in Example 1 of DE-A 100 46 957 (However, the bed height in the decomposition (chambers 1 to 4) amounts to advantageously 44 mm with a residence time per chamber of 1.46 h and in the calcination (chambers 5 to 8), it amounts to advantageously 130 mm at a residence time of 4.67 h) by means of a belt calciner; the chambers have a base area (with a uniform chamber length of 1.40 m) of 1.29 m ² (decomposition) and 1.40 m ² (calcination) and are from below through the coarse-mesh band of 50-150 Nm ³ / h Incoming air flows through; In addition, the air is circulated by rotating fans (900 to 1500 rpm). Within the chambers, the temporal and local deviation of the temperature from the setpoint is always ≤ 2 ° C. Otherwise, as in Example 1 of DE-A 100 46 957 described procedure.

The resulting shaped catalyst bodies are suitable in the same As a catalyst for the described partial oxidation from propylene to acrolein.

B) Production and testing of annular Full catalyst moldings with the following stoichiometry Active composition and using various graphites as molding aids:

• Mo ₁₂ Co ₇ Fc _2.94 Bi _0.6 Si _1.59 K _0.08 O _x

At 60 ° C 213 kg of ammonium heptamolybdate tetrahydrate (81.5 wt .-% MoO ₃ ) were dissolved in 600 l of water. In this solution, while maintaining the 60 ° C 0.97 kg of 46.8 wt .-% aqueous Stirred in potassium hydroxide solution of 20 ° C (thereby a solution A was obtained).

A second solution B was prepared by stirring to 333.7 kg of an aqueous cobalt (II) nitrate solution (12.4 wt.% Co) at 30 ° C, 116.25 kg of an aqueous iron containing 20 ° C - (III) nitrate solution (14.2 wt% Fe). After the addition was still 30 mm. stirred at 30 ° C. Thereafter, at 60 ° C., 112.3 kg of an aqueous bismuth nitrate solution (11.2% by weight of Bi) containing 20 ° C. was stirred to obtain the solution B. Within 30 mm. at 60 ° C, the solution B was stirred into the solution A. 15 minutes. After stirring was completed at 60 ° C 19.16 kg of silica sol (Fa. Du Pont, type Ludox ^® , 46.80 wt .-% SiO ₂ , density: 1.36 to 1.42 g / cm ³ , pH = 8.5 to 9.5, alkali content max 0.5 wt%) was added to the resulting mash. While maintaining the 60 ° C was still 15 min. stirred. Then, the mash obtained was spray-dried in a hot air countercurrent process (gas inlet temperature: 400 ± 10 ° C, gas outlet temperature: 140 ± 5 ° C) to obtain a spray powder whose ignition loss (3 hours at 600 ° C under air) was 30% of its weight. The spray powder had a d ₅₀ of 20.3 microns and a d ₁₀ of 3.24 microns and a d ₉₀ of 53.6 microns.

In Aliquots of the spray powder obtained were each additional 1.5 wt .-% (based on the spray powder) of the respective finely divided graphite mixed.

The each resulting dry mixture was by means of a Kompaktors the company Hosokawa Bepex GmbH (D-74211 Leingarten) of the Kompaktor type K 200/100 under the conditions of 2.8 mm gap width, 1.0 mm mesh, 400 μm mesh undersize, 60 kN pressing force and 65 to 70 rpm screw speed by precompacting to a substantially uniform grain size from 400 μm to 1 mm coarsened. The compact had a hardness of 10 N.

The Kompaktat was then with, based on its weight, another 2 wt .-% of the same graphite mixed and then in a Kilian rotary machine (tabletting machine) of the type R × 73, the company Kilian, D-50735 Cologne, under a nitrogen atmosphere to annular Vollkatalysatorvorläuferformkörpern with non-curved face of geometry 5 mm × 3 mm × 2 mm (A × H × I) with a lateral compressive strength of 20 ± 1 N compressed.

• – mit 1°C/min. von 25°C auf 160°C erhöht;
• – dann 100 min. bei 160°C gehalten;
• – danach mit 3°C/min. von 160°C auf 200°C erhöht;
• – dann 100 min. bei 200°C gehalten;
• – danach mit 2°C/min. von 200°C auf 230°C erhöht;
• – dann 100 min. bei 230°C gehalten;
• – danach mit 3°C/min. von 230°C auf 270°C erhöht;
• – dann 100 min. bei 270°C gehalten;
• – danach mit 1°C/min. auf 380°C erhöht;
• – dann 4,5 h bei 380°C gehalten;
• – danach mit 1°C/min. auf 430°C erhöht;
• – dann 4,5 h bei 430°C gehalten;
• – danach mit 1°C/min. auf 500°C erhöht;
• – dann 9 h bei 500°C gehalten;
• – danach innerhalb von 4 h auf 25°C abgekühlt.

For the final thermal treatment in each case 1900 g of Vollkatalysatorvorläuferformkörper in a heated circulating air chamber (0.12 m ³ internal volume) were added (2 Nm ³ air / min.). Subsequently, the temperature in the bed was changed as follows:

• - at 1 ° C / min. increased from 25 ° C to 160 ° C;
• - then 100 min. kept at 160 ° C;
• - afterwards with 3 ° C / min. increased from 160 ° C to 200 ° C;
• - then 100 min. kept at 200 ° C;
• - afterwards with 2 ° C / min. increased from 200 ° C to 230 ° C;
• - then 100 min. kept at 230 ° C;
• - afterwards with 3 ° C / min. increased from 230 ° C to 270 ° C;
• - then 100 min. maintained at 270 ° C;
• - afterwards with 1 ° C / min. increased to 380 ° C;
• - Then held at 380 ° C for 4.5 h;
• - afterwards with 1 ° C / min. increased to 430 ° C;
• - Then held at 430 ° C for 4.5 h;
• - afterwards with 1 ° C / min. increased to 500 ° C;
• - then held at 500 ° C for 9 h;
• - Then cooled within 4 h at 25 ° C.

there were made from the annular unsupported catalyst precursor bodies obtained ring-shaped Vollkatalysatorformkörper.

(Instead of carrying out the thermal treatment as described, it can also be used as in Example 3 of the DE-A 100 46 957 described by means of a Bandcalziniervorrichtung perform; The chambers have a base area (with a uniform chamber length of 1.40 m) of 1.29 m ² (decomposition, chambers 1-4) and 1.40 m ² (calcination, chambers 5-8) and are from below through the coarse-mesh band of 70-120 Nm ³ / h supply air, preferably of 75 Nm ³ / h supply air, flows through; in addition, the air is circulated by rotating fans (900 to 1500 rpm); within the chambers, the temporal and local deviation of the temperature from the target value was always ≤ 2 ° C; the annular unsupported catalyst precursor bodies are guided through the chambers at a layer height of 50 mm to 110 mm, preferably 50 mm to 70 mm; Otherwise, as in Example 3 of DE-A 100 46 957 described method; the resulting annular unsupported catalysts, like the unsupported catalyst bodies obtained in A), can be used for the gas-phase catalytic partial oxidation of propene to acrolein described in A) 4).

The obtained annular unsupported catalysts were as in A) 4. described as catalysts for a heterogeneous catalyzed partial gas phase oxidation of propene to acrolein used as catalysts (with the difference that the Prefill in the reaction tube over a length of 30 cm of steatite rings of geometry 5 mm × 3 mm × 2 mm (A × H × I) and on a bulk length of 70 cm consisted of the Vollkatalysatorformkörpern).

The selectivities S ^{A of} the acrolein formation (also after 120 hours of operation) were: Used graphite S ^A (mol%) V1 89.8 V2 89.9 V3 90.5 B1 90.8 B2 91.0

C) For the production and testing of annular Full catalyst moldings with the following stoichiometry the active composition and using various graphites as molding aids:

• Mo ₁₂ P _1.5 V _0.6 Cs _1.0 Cu _0.5 Sb ₁ S _0.04 O _x

In 619 l at 45 ° C tempered water in a water-tempered jacketed vessel with stirring (70 revolutions per minute (RPM)) 537.5 kg of ammonium heptamolybdate tetrahydrate ((NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O (81 wt .-% MoO ₃ , 8% by weight of NH ₃ , ≦ 50 ppm by weight of Na and ≦ 100 ppm by weight of K), the temperature of the solution hereby dropped to 37 ° C. In order to ensure reliable dissolution of the ammonium heptamolybdate, After the end of the metered addition, stirring was continued for a further 15 minutes while maintaining the temperature at 37 ° C. With further stirring, 17.82 kg of ammonium metavanadate (NH ₄ VO ₃ , 77% by weight of V ₂ O ₅ , 14.5% by weight of NH ₃ , ≦ 150 ppm by weight of Na and ≦ 500 ppm by weight of K) was stirred in. The mixture was stirred for 2 minutes and then within one minute a colorless, clear, 60 ° C warm solution of 49.6 kg cesium nitrate (CsNO ₃ with 72 wt .-% Cs ₂ O and ≤ 50 ppm by weight Na, ≤ 1 00 ppm by weight K, ≦ 10 ppm by weight Al and ≦ 20 ppm by weight Fe) are stirred into 106 l of water. In this case, the temperature of the resulting suspension rose to 39 ° C. After stirring for one minute, 31.66% by weight of 175% strength by weight phosphoric acid (density at 25 ° C. and 1 atm: 1.57 g / ml, viscosity at 25 ° C. and 1 atm: 0.147 cm ² / S) added. Due to the exothermic reaction, the temperature rose to 42 ° C. Again, stirring was continued for 1 minute. Then 1.34 kg of ammonium sulfate ((NH ₄ ) ₂ SO ₄ (> 99 wt .-%)) were stirred in within one minute and stirred for a further 1 minute. 37.04 kg antimony trioxide (Sb ₂ O ₃ , particle diameter d ₅₀ = approx. 2 μm, crystal structure according to XRD:> 75% senarmontite, <25% valentineite, purity:> 99, with constant stirring at identical temperature within 3 minutes 3 wt .-%, <0.3 wt .-% As ₂ O ₃ , ≤ 0.3 wt .-% PbO and ≤ 300 ppm by weight FeO) was added (commercially available as Triox White, Code No. 639000 of Fa. Antraco, D-10407 Berlin). Now the stirrer speed was reduced from 70 to 50 rpm. Subsequently, the stirred suspension was heated by steam in a double jacket within 30 minutes linearly to 95 ° C. At this temperature and 50 rpm, 51.64 kg of copper nitrate solution (aqueous Cu (NO ₃ ) ₂ solution containing 15.6% by weight of Cu) were added over the course of 4 minutes. After four minutes of stirring at 95 ° C, the stirring speed was further reduced from 50 to 35 rpm. Subsequently, the entire suspension was drained within 4 minutes in a nitrogen-overlaid, tempered at 85 ° C and stirred at 35 rpm stirring tower reservoir tank and it was rinsed with 20 liters of water (25 ° C). From this, the suspension was spray-dried in a rotary disk spray tower in countercurrent with an inlet temperature of 285 ° C and an outlet temperature of 110 ° C within 3.5 h, the resulting spray powder loss on ignition (1 h at 500 ° C in air) of about 16 wt .-% had.

The spray powder was homogeneously mixed and compacted with 1.5% by weight of the respective graphite (Kompaktor from Hosokawa Bepex GmbH, D-74211 Leingarten, type K200 / 100 with concave, corrugated smooth rolls, gap width: 2.8 mm, mesh width : 1.25 mm, mesh size undersize: 400 μm, screw speed: 65 to 70 rpm). For tableting, the compactate was admixed with an additional 1% by weight of the same graphite mixed. Subsequently, the compactate in a Kilian rotary machine (tableting machine of the type R × 73 from Messrs. Kilian, D-50735 Cologne) under nitrogen atmosphere to annular Vollringtabletten the geometry 7 mm × 7 mm × 3 mm (outer diameter × height × inner diameter) with a lateral compressive strength of 35 ± 2 N tabletted.

8 kg of the raw tablets were uniformly distributed in a wire container of the base area 33.0 cm × 49.5 cm, resulting in a bed height of 4 cm. The wire container was placed in a chamber furnace (Elino Industrie-Ofenbau, Carl Hanf GmbH & Co., D-52355 Düren, type KA-040 / 006-08 EW.OH, dimensions: length = 57 cm, width = 57 cm, height = 80 cm) arranged so that the bed of tablets was flowed through evenly. 2 Nm ³ / h of fresh air were supplied and the air circulation in the oven adjusted so that the bed at a rate of 0.9 m / s (determined by aerometer, Messrs. Testo, type 445) was flowed through. The oven was then heated to 380 ° C. with the following temperature ramp: heating to 180 ° C. within 40 minutes, holding for 30 minutes, heating to 220 ° C. within 10 minutes, holding for 30 minutes, to 270 ° C. within 13 minutes Heat up, hold for 30 min, heat to 340 ° C within 25 min and then to 380 ° C within 40 min. This temperature was then held for 390 minutes. Meanwhile, the NH ₃ content in the extracted atmosphere of the thermal treatment was continuously monitored by FTIR spectroscopy (Nicolet spectrometer, "Impact" type, IR stainless steel cell with CaF ₂ window, 10 cm layer thickness, temperature control to 120 ° C. , Determination of the concentration on the basis of the intensity of the band at 3333 cm ^-1 ) The NH ₃ content remained during the entire thermal treatment ≤ 2.4 vol .-% This maximum value was reached at 220 ° C. The thus obtained annular shaped catalyst bodies all had a lateral compressive strength of 15 ± 2 N, an ammonium content (determined by Kjeldahl titration) of 0.3% by weight NH ₄ ⁺ and a MoO ₃ content of 2 XRD intensity%, the latter being calculated as the ratio of the intensity of the (021) MoO ₃ reflection at 2Θ = 27.3 ° to the intensity of the (222) reflection of the heteropoly compound at 2Θ = 26.5 ° in the X-ray powder diffractogram (with Cu-Kα radiation).
(As an alternative to the described calcining in the chamber furnace, the calcination can also be carried out here in the belt calciner, as described in A).)

to Testing of the respectively obtained annular unsupported catalysts for a heterogeneously catalyzed partial oxidation of methacrolein to methacrylic acid were each 2 kg of the thus prepared annular shaped catalyst bodies having a and a repackage of 50 g steatitrings each (Steatite C220 of Fe. CeramTec) of geometry 7 mm × 7 mm × 4 mm outside diameter × height × inside diameter in a stainless steel model tube (outer diameter = 30 mm, inner diameter = 26 mm, length = 4.15 m) filled (filling height: 397 cm). This was in a nitrogen-bubbled, on Salt bath at 287 ° C. The catalytic testing was carried out under recycle gas method: The reactor exit gas was in this case drove a venturi, there with 75 ° C warm Water quenched and then into the swamp to 75 ° C tempered distillation column A passed. Approximately 55 kg / day one Mixture of reaction product and water (typically about 9.5 Wt .-% methacrylic acid, about 0.8 wt .-% acetic acid and about 0.1% by weight of acrylic acid in water) were taken out here. The depleted gas stream passed into the column A. In the middle a partial stream was taken and down to 7 ° C tempered column B passed.

With a fed at the top of the column B solution of 6 wt .-% hydroquinone in water (2 kg / h), the exhaust gas was freed in this column of the remaining organic components and escaped at the top of the column. The contents of the bottom of column B (essentially about 1.4% by weight of methacrolein in water) were pumped to the top of column A; 220 g / h of methacrolein were additionally fed there. At the top of column A 1700 Nl / h of circulating gas were withdrawn at a head temperature of 66 ° C, mixed with 450 Nl / h of fresh air and as educt gas the about 5 vol .-% methacrolein, about 12 vol .-% O ₂ , about 21% by volume of water vapor, about 2.5% by volume of CO, about 3% by volume of CO ₂ and further inert gas (essentially nitrogen) were passed into the reactor. This resulted in a mass-related space velocity (WHSV) of 0.17 h ^-1 .

While In the 5-day test, methacrolein sales in the simple passage maintained at 65 mol%; this was the salt bath temperature gradually increased.

On the 5th day, depending on the graphite used, the following selectivities S ^{MA of} the methacrylic acid formation resulted: graphite S ^MA (mol%) V1 85.3 V2 85.2 V3 85.6 B1 86.0 B2 86.2

D) Preparation and testing of annular Full catalyst moldings with a vanadium, phosphorus, Iron and oxygen comprehensive Multimetalloxidaktivmasse and under Use of various graphites as shaping aids

4602 kg of iso-butanol were initially charged in an 8 m ³ steel / enamel stirred tank with baffles, which had been rendered inert by means of nitrogen and were externally heated by pressurized water. After starting up the three-stage impeller stirrer, the isobutanol was heated to 90 ° C. under reflux. At this temperature, a screw conveyor with the addition of 690 kg of vanadium pentoxide was started. After about 20 minutes about 2/3 of the desired amount of vanadium pentoxide were added, with further addition of vanadium pentoxide with the pumping of 805 kg of a temperature of 50 ° C having polyphosphoric acid having a P ₂ O ₅ content of 76 wt .-% (equivalent to 105 wt .-% H ₃ PO ₄ ) started. After complete addition of the phosphoric acid, the reaction mixture was heated to reflux at about 100 to 108 ° C and left under these conditions for 14 hours. Subsequently, the hot suspension was cooled to 60 ° C within 70-80 minutes and 22.7 kg Fe (III) phosphate (29.9% by weight Fe) was added. After re-heating within 70 minutes at reflux, the suspension boiled under reflux for a further hour. Subsequently, the suspension was discharged into a previously inertized with nitrogen and heated Druckfilternutsche and filtered off at a temperature of about 100 ° C at a pressure above the suction filter of up to 0.35 MPa abs. The filter cake was blown dry by continuous introduction of nitrogen at 100 ° C and with stirring with a centrally arranged, height-adjustable stirrer within about one hour. After dry-blowing was heated to about 155 ° C and evacuated to a pressure of 15 kPa abs (150 mbar abs). The drying was carried out to a residual iso-butanol content of <2 wt .-% in the dried catalyst precursor composition.

The Fe / V ratio was 0.016.

Subsequently, the dried powder was treated under air for 2 hours in a rotary tube having a length of 6.5 m, an inner diameter of 0.9 m and internal helical coils (for mixing purposes). The speed of the rotary tube was 0.4 U / min. The powder was fed into the rotary kiln at a rate of 60 kg / h. The air supply was 100 m ³ / h. The temperatures of the five equal heating zones measured directly on the outside of the externally heated rotary kiln were 250 ° C, 300 ° C, 345 ° C, 345 ° C and 345 in the "from the exit of the powder" to the "powder inlet" ° C.

The The precursor material removed from the rotary tube was mixed with 1% by weight. the respective graphite in a Rhönradmischer intimately and homogeneously mixed. The resulting mixture was then in a Laboratory calender with 2 counter-rotating steel rollers at one Compacting pressure of 9 bar and through a sieve with a mesh size of 0.8 mm. The resulting Kompaktat had a substantially uniform grain size of ≥ 0.4 mm and ≤ 0.8 mm. It was with another 2 wt .-% of respective graphite mixed in a Rhönradmischer, and in a tabletting machine (tableting machine of the type Kilian LX 18 (Kilian, D-50735 Cologne) pressing force 5.3 N) to 5 × 3.2 × 2.5 mm hollow cylinders (outer diameter × height × diameter of the inner hole). These had a lateral compressive strength from 11 N up.

The obtained 5 × 3.2 × 2.5 mm (A × H × I) hollow cylinders were molded according to the WO 03/78059 , Page 39 calcined under Example 9 to the respective shaped catalyst bodies.

For the purpose of testing each of the obtained shaped catalyst bodies as catalysts in a process of heterogeneously catalyzed partial gas phase oxidation of n-butane to produce maleic anhydride, a pilot plant equipped with a feed unit and a tube bundle reactor unit was used. The plant was operated in the "straight passage", as in the EP-B 1 261 424 described.

The hydrocarbon was added in a controlled amount in liquid form via a pump. When Oxygen-containing gas was added volume-controlled air. Triethyl phosphate (TEP) was also added in a controlled amount, dissolved in water, in liquid form.

The Tube bundle reactor unit consisted of a tube bundle reactor with a reactor tube. The length of the reactor tube made of stainless steel was 6.5 m, the inner diameter 22.3 mm, the wall thickness 2.3 mm. Inside the reactor tube was in an axially centered protective tube with 6 mm outer diameter a multi-thermocouple with 20 Temperature measurement. The temperature of the reactor tube took place by a heat transfer circuit with a length of 6.5 m. As heat transfer medium a molten salt was used.

The Reactor tube was from the reaction gas mixture from top to bottom flows through. The upper 0.2 m of the 6.5 m long reactor tube remained unfilled. Next came a 0.3 m long preheating zone, which with steatite from Steatite C220 geometry 5 × 3.2 × 2 mm (A × H × I) was filled as inert material. After the preheating zone followed the catalyst bed, which in total each 2180 ml of catalyst.

Directly after the tube bundle reactor unit became gaseous Product taken and the gas chromatographic online analytics fed. The main stream of the gaseous reactor discharge was ejected from the plant.

The composition of the feed gas mixture was 2 vol.% n-butane, 3 vol.% H ₂ O, 2.25 ppm by volume TEP and as residual quantity Air.

Of the Inlet pressure was 3.3 bar. The total load of the fixed catalyst bed (pure inert material sections are not included) was 2000 Nl / (lh), the salt bath temperature (about 415 ° C) each adjusted so that the butane conversion, based on one-off Passage, 85 mol%.

After an operating time of the test plant of 150 h in each case, the selectivity of the maleic anhydride formation S ^{MAH was} determined.

The values were as follows, depending on the graphite used: graphite S ^MAH (mol%) V1 56.9 V2 56.8 V3 57.1 B1 57.5 B2 57.4

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 2005/030393 [0002, 0007, 0008, 0049]
• - EP 467144 A [0002, 0007, 0049, 0161, 0162, 0166]
• WO 01/68245 [0002, 0007, 0045, 0045, 0049, 0169]
• - DE 10353014 A [0006]
• - DE 10360396 A [0006]
• DE 102005035978 A [0007, 0045, 0045, 0049, 0169]
• - EP 1060792 A [0007, 0045, 0045, 0049, 0049]
• - WO 03/078310 [0007, 0045, 0049, 0049, 0168, 0168, 0168, 0168, 0168, 0168, 0169]
• WO 03/78059 [0007, 0045, 0045, 0049, 0220]
• - DE 102005037678 A [0007, 0045, 0045, 0049]
• US 2005/0131253 A [0010, 0045, 0045, 0049]
• WO 02/062737 [0044, 0045, 0045, 0049]
• WO 03/78310 [0045]
• - DE 19855913 A [0045, 0045, 0049]
• WO 02/24620 [0045, 0045, 0049, 0096]
• - DE 19922113 A [0045, 0045, 0049]
• - EP 467114 A [0045, 0045]
• WO 05/030393 [0045, 0045]
• EP 184790A [0080]
• - DE 10046957 A [0096, 0197, 0197, 0206, 0206]
• - DE 4407020 A [0108, 0111, 0118, 0137]
• EP 835A [0108, 0111]
• - EP 575897 A [0108, 0118]
• - DE 3338380 C [0108, 0111]
• DE 10325487A [0110]
• WO 00/53557 [0118, 0146, 0146]
• WO 00/53558 [0118, 0146]
• - DE 19910506 A [0118, 0145]
• - EP 1106598 A [0118, 0134, 0134, 0134, 0145, 0146]
• WO 01/36364 [0118, 0146]
• - DE 19927624 A [0118]
• - DE 19948248 A [0118, 0146]
• - DE 19948523 A [0118, 0146]
• - DE 19948241 A [0118]
• - EP 700714 A [0118, 0143, 0146]
• - DE 10313213 A [0118, 0145, 0146]
• - DE 10313209 A [0118, 0146]
• - DE 10232748 A [0118, 0141]
• - DE 10313208 A [0118, 0145, 0146]
• WO 03/039744 [0118]
• - EP 279374A [0118]
• - DE 3338380 A [0118]
• - DE 3300044 A [0118]
• - DE 102004003212 A [0118]
• - DE 102005013039 A [0118]
• - DE 102005009891 A [0118]
• - DE 102005010111 A [0118]
• - DE 102005009885 A [0118]
• - EP 990636 A [0134, 0134]
• - DE 10246119 A [0135]
• - DE 10245585 A [0135]
• - DE 4431957 A [0143]
• - EP 700893 A [0143]
• EP 468290 B [0144]
• DE 19746210 A [0156]
• EP 015565 A [0156]
• DE 10063162 A [0157, 0157, 0157, 0157]
• - DE 10337788 A [0158]
• WO 03078310 [0169]
• - EP 962253 A [0170]
• - DE 10122027 A [0170, 0172]
• - EP 608838 A [0170, 0173]
• - DE 19835247 A [0170]
• - EP 895809 A [0170]
• - EP 1254709A [0170]
• - EP 1192987 A [0170]
• - EP 1262235 A [0170]
• - EP 1193240 A [0170]
• - JP 11-343261 A [0170]
• JP 11-343262 A [0170]
• - EP 1090684 A [0170, 0173]
• - EP 1301457 A [0170]
• EP 1254707A [0170]
• - EP 1335793 A [0170]
• - DE 10046672 A [0170, 0173]
• - DE 10034825 A [0170]
• EP 1556337A [0170]
• DE 10033121 A [0170]
• WO 01/98246 [0170]
• EP 1558569 A [0170]
• - DE 102004025445 A [0173]
• DE 2351151 A [0173, 0173, 0173]
• DE 2526238 A [0173, 0173]
• - EP 092097 A [0173]
• - EP 58927A [0173]
• - DE 4132263 A [0173]
• - DE 4132684 A [0173]
• - DE 4022212 A [0173]
• - EP 522871 A [0173]
• - DE 2106796 A [0173]
• - DE 1624921 A [0173]
• GB 1464198 A [0173]
• - GB 1291354 A [0173]
• - DE 2025430 A [0173]
• DE 1254137A [0173]
• - DE 2159346 A [0173]
• - EP 372972 A [0173]
• WO 89/07101 [0173]
• - DE 4311608 A [0173]
• - DE 10131297 A [0173]
• - EP 529853 A [0173]
• WO 01/96270 [0173]
• - DE 10028582 A [0173]
• - EP 1261424 B [0221]

Cited non-patent literature

• - "Quantitative Organic Elemental Analysis ", VON Verlagsgesellschaft mbH, Weinheim, Issue 1991; ISBN: 3-527-28056-1, page 225 ff. [0040]
• Beyer, Lehrbuch der organischen Chemie, 17th Edition (1973), Hirzel Verlag, Stuttgart, p. 261 [0173]

Claims (28)

A process for preparing shaped catalyst bodies whose active composition is a multielement oxide in which a finely divided precursor mixture containing graphite added as a finely divided molding aid forms the desired geometry and the resulting Katalysatorvorläuferformkörper at elevated temperature to obtain the shaped catalyst body whose active material is a Multielementoxid , thermally treated, characterized in that a) for the specific surface area O _{G of} the finely divided graphite: 0.5 m ² / g ≦ O _G ≦ 5 m ² / g, and b) for the particle diameter d _{50 of} the finely divided graphite : 40 μm ≤ d ₅₀ ≤ 200 μm. A method according to claim 1, characterized in that for the finely divided graphite is: 60 microns ≤ d ₅₀ ≤ 200 microns and 0.5 m ² / g ≤ O _G ≤ 5 m ² / g. A method according to claim 1, characterized in that for the finely divided graphite applies: 90 microns ≤ d ₅₀ ≤ 200 microns, 20 microns ≤ d ₁₀ ≤ 90 microns, 150 microns ≤ d ₉₀ ≤ 300 microns, and 0.5 m ² / g ≤ O _G ≤ 5 m ² / g. Method according to one of claims 1 to 3, characterized in that the finely divided precursor mixture, based on its total weight, 0.1 to 20 wt .-% of finely divided Contains added graphite. Method according to one of claims 1 to 4, characterized in that in the thermal treatment of Katalysatorvorläuferformkörper until receipt the shaped catalyst body 1 to 70 wt .-% of that in the catalyst precursor moldings contained graphite in gaseous escaping compounds is converted. Method according to one of claims 1 to 5, characterized in that the thermal treatment of the catalyst precursor moldings takes place in an oxidizing atmosphere. Method according to one of claims 1 to 6, characterized in that the thermal treatment of the catalyst precursor moldings at temperatures of 150 to 650 ° C. Method according to one of claims 1 to 7, characterized in that the thermal treatment of the catalyst precursor moldings done in the air stream. Method according to one of claims 1 to 8, characterized in that the finely divided graphite is natural graphite. 10. The method according to any one of claims 1 to 9, characterized in that the finely divided graphite has a temperature T _{i of} the combustion onset, which is at least 50 ° C greater than that in the thermal treatment of the catalyst precursor moldings to this for a period of at least 30 minutes acting highest temperature. Method according to one of claims 1 to 10, characterized in that T _{i of} the finely divided graphite ≥ 500 ° C. Method according to one of claims 1 to 11, characterized in that the maximum combustion temperature T _{m of} the finely divided graphite ≥ 680 ° C. Method according to one of claims 1 to 12, characterized in that the particle diameter of the finely divided Precursor mixture except the added molding aid, in the range 10 to 2000 microns. Method according to one of claims 1 to 13, characterized in that the shaping to the desired Geometry is done by tableting. Method according to one of claims 1 to 14, characterized in that the shaping is carried out using a molding pressure of 50 kg / cm ² to 5000 kg / cm ² . Method according to one of claims 1 to 15, characterized in that the shaped catalyst body is a ball with a diameter of 2 to 10 mm. Method according to one of claims 1 to 15, characterized in that the shaped catalyst body a solid cylinder, is its outer diameter and length 2 to 10 mm. Method according to one of claims 1 to 15, characterized in that the shaped catalyst body a ring is whose outside diameter and length 2 to 10 mm and whose wall thickness is 1 to 3 mm. Method according to one of claims 1 to 18, characterized in that the active composition is a Mulitmetalloxid is. Method according to one of claims 1 to 18, characterized in that the active composition is a multi-element oxide is this a) the elements Mo, Fe and Bi, or b) the elements Mo and V, or c) the elements Mo, V and P, or d) the Elements V and P includes. Catalyst molding, available according to a method according to one of the claims 1 to 20. Process of a heterogeneously catalyzed gas phase reaction, characterized in that the catalyst used at least a shaped catalyst body according to claim 21 includes. Method according to claim 22, characterized in that that the heterogeneously catalyzed gas phase reaction is a heterogeneous catalyzed partial oxidation of an organic compound. Method according to claim 23, characterized that the heterogeneously catalyzed partial oxidation the partial oxidation from propene to acrolein and / or acrylic acid. Method according to claim 23, characterized that the heterogeneously catalyzed partial oxidation the partial oxidation from propane to acrolein and / or acrylic acid. Method according to claim 23, characterized that the heterogeneously catalyzed partial oxidation the partial oxidation from isobutene or tert-butanol to methacrolein. Method according to claim 23, characterized that the heterogeneously catalyzed partial oxidation the partial oxidation from methacrolein to methacrylic acid. Method according to claim 23, characterized that the heterogeneously catalyzed partial oxidation the partial oxidation from acrolein to acrylic acid. Method according to claim 23, characterized that the heterogeneously catalyzed partial oxidation the partial oxidation a hydrocarbon having at least 4 carbon atoms to maleic anhydride is.